Chocolate and Raspberry Mousse Cake with Dark Chocolate Mirror Glaze

chocolate raspberry mousse cake
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For obvious reasons, I haven’t made many fancy cakes this past year. It’s hard to work up the enthusiasm when sharing celebrations with your extended family and friends isn’t an option (Zoom doesn’t count). But this week was my husband’s birthday, his second pandemic one. And even if the days of the past year have crawled along ever so slowly (especially lately — pandemic fatigue is real, I tell you), it still felt necessary to acknowledge their passing. With cake.

There’s a recipe called David’s Chocolate Raspberry Cake in my book. It’s his favorite, the classic combination of deep chocolate cake, bright raspberries, and silky chocolate frosting. He would have been more than happy with that, but I was in the mood for a Project. I didn’t dare stray from the chocolate-raspberry flavor combination, so this was all about repackaging. We start with the same chocolate cake, but this time the raspberry shows up an an intense gelée, a smooth crémeux (basically a fancy set pudding), and in the rich chocolate mousse. All of that is doused in a gloriously shiny glaze and sprinkled with chocolate crumbs (which taste like oreos) for texture. It was good, very good.

chocolate raspberry mousse cake inside

Tips for making mousse cakes

It’s all about the timing

Layered mousse cakes look impressive and complicated, but they aren’t necessarily more difficult to assemble than a “regular” layer cake. While there are several components, none are difficult to prepare and most can be made ahead of time. I suggest spreading the work out over a few days to keep the process relaxed and fun. For example, this is the schedule I followed:

  • Day 1: Make chocolate cake (store in fridge), gelée (freeze), and crémeux (freeze)
  • Day 2: Make chocolate crumbs, chocolate mousse, and assemble cake (freeze overnight)
  • Day 3 (serving day): Make glaze, glaze and decorate frozen cake, defrost in fridge, eat!

You can definitely condense the project into 2 days. However, the key timing points are to make sure the gelée/crémeux are frozen before assembly, the mousse is used right before assembly, and the entire cake is frozen before glazing. Once glazed, the cake will need at least 2 hours in the fridge to defrost before eating.

chocolate mirror glaze

Useful equipment

There are a few pieces of equipment that make assembling mousse cakes straightforward and produce sleek results.

  • Cake ring: Mousse cakes are often assembled in stainless steel rings that act as molds. I used a 6×3 cake ring.
  • Acetate: Also known as cake collars, these thin, transparent sheets line the cake ring and make the frozen cake easy to unmold. I used 3″ high acetate cut to fit the ring.
  • Instant-read digital thermometer: Important for the crémeux and mirror glaze, which are cooked or cooled to exact temperatures for best results. My favorite is the Thermapen.
  • Immersion blender: Not strictly necessary, but does help remove lumps from mirror glaze for a smooth finish. I use this Hamilton Beach immersion blender.

Specialty ingredients

  • Powdered gelatin: Gelatin is the setting agent in several layers. I generally use powdered because it’s readily available in my area. You’ll need 26g total (if you’re using packets, this is a little less than 4 packets).
  • Ruby chocolate: Ruby chocolate is a special variety of chocolate that is naturally pink. It has a unique fruity flavor that pairs really well with raspberries. I use Callebaut brand.
  • Raspberry puree: You will need 260g raspberry puree total for all the components. You can buy pre-made puree online from some specialty baking / food stores, or make your own. To make raspberry puree, I simply blended one 400g bag of frozen raspberries (after thawing). I used puree with seeds for the gelée, but strained out the seeds for the crémeux and mousse. I had just enough puree; so if you want to use all seedless I would start with ~550g frozen raspberries to ensure you have enough after straining.

Baker’s notes:

  • Before making the dark chocolate raspberry mousse, I recommend having your cake and gelée-crémeux layers trimmed and all your equipment for assembly ready to go. The gelatin in the mousse will begin setting as soon as you add the cream, and the longer you wait the harder it will be to spread.
  • I had intended to use another layer of cake but didn’t have quite enough room on after adding the gelée and crémeux. Next time I make this, I’ll put the first round of cake directly on the bottom of the cake ring and pipe mousse around it. That should give just enough room for another extra cake layer.
  • I didn’t use a piping bag to add the mousse and ended up missing a couple spots around the crémeux. I filled them in with some ganache before glazing, and that worked ok. But after about a day in the fridge the glaze sort of wrinkled where the ganache was (probably because it was a different density compared the mousse). So I definitely recommend using a piping bag and taking care to get all the edges filled with mousse for the cleanest finish!
  • The recipe for chocolate crumb makes quite a lot; feel free to cut in half or even a quarter depending on how much you want to use for garnish. I made a full batch to freeze extras for snacking and other projects.

Chocolate and Raspberry Mousse Cake with Dark Chocolate Mirror Glaze

Makes one 6×3 mousse cake (serves 8-12) | Chocolate cake recipe adapted from Baked to Order; raspberry gelée, dark chocolate raspberry mousse, and dark chocolate glaze adapted from Dominique Ansel’s Everyone Can Bake; ruby raspberry crémeux adapted from Felicia Mayden; chocolate crumb adapted from Milk

Ingredients:

For the chocolate cake (Makes one 8″ round):
  • 57g unsalted butter, cubed
  • 27g neutral vegetable oil
  • 60g whole milk
  • 1 tsp vanilla extract
  • 125g all-purpose flour
  • 34g Dutch-processed cocoa powder
  • 165g light brown sugar
  • 1/2 tsp kosher salt
  • 3/4 tsp baking soda
  • 80g sour cream, at room temperature
  • 1 large egg, at room temperature
  • 60g freshly brewed coffee
For the raspberry gelée (makes about 240g or 1 cup):
  • 20g cold water
  • 4g (scant 1 1/4 tsp) powdered gelatin
  • 185g raspberry puree (with or without seeds)
  • 30g granulated sugar
For the ruby raspberry crémeux (makes about 435g or 1 3/4 c):
  • 140g heavy cream (35%), divided
  • 3g (1 tsp) powdered gelatin
  • 115g ruby chocolate, chopped
  • 20g corn syrup
  • 1 egg yolk
  • 100g whole milk
  • 40g seedless raspberry puree
For the chocolate crumb (makes about 350g or 2 1/2 c):
  • 105g all-purpose flour
  • 4g (1 tsp) cornstarch
  • 100g granulated sugar
  • 65g Dutch-processed cocoa powder
  • 4g (1 tsp) kosher salt
  • 85g butter, melted
For the dark chocolate raspberry mousse (makes about 750g or 3 c):
  • 7g (2 1/4 tsp) powdered gelatin
  • 214g dark chocolate, chopped (I used half 54.5% Callebaut, half 70% Callebaut)
  • 182g whole milk, divided
  • 35g seedless raspberry puree
  • 315g cream (35%)
For the dark chocolate mirror glaze (makes about 500g or 2 c):
  • 60g cold water
  • 12g (4 tsp) powdered gelatin
  • 70g unsweetened cocoa powder (Dutch-processed)
  • 140g heavy cream
  • 75g room temperature water
  • 200g granulated sugar

To assemble:

Method:

For the chocolate cake:

Preheat the oven to 350°F (175°C) with a rack in the middle. Grease an 8-inch round cake pan and line the bottom with parchment paper, then grease the pan again and dust with the cocoa powder.

In a small saucepan, melt the butter over low heat. When the butter has melted, remove from the heat, and whisk in the oil, milk, and vanilla. Allow to cool slightly while you prepare the rest of the ingredients.

Sift together the flour, cocoa powder, sugar, salt, and baking soda in a large bowl. Set aside.

Whisk the sour cream into the butter mixture, followed by the egg. Whisk the wet ingredients into the dry until combined. Add the hot coffee and whisk just until smooth.

Scrape the batter into the prepared pan and bake until a skewer inserted into the center comes out with just a few moist crumbs, about 25-32 minutes. Transfer to a wire rack to cool. Once the pan is cool enough to handle, run an offset spatula around the edge and turn the cake out to finish cooling completely. Wrap and chill the cake in the fridge until ready to assemble.

For the raspberry gelée:

Line a 6-inch cake pan with plastic wrap. Set aside.

Bloom the gelatin: Combine the cold water and gelatin in a small bowl. Stir with a spoon until the gelatin has dissolved. Allow to bloom for 5-10 minutes.

Cook the gelée: In a medium saucepan, bring the raspberry puree and sugar to a simmer over medium heat, whisking occasionally. Once the mixture comes to a simmer, remove from heat. Add the gelatin mixture and whisk to combine, making sure the gelatin completely dissolves.

Set the gelée: Pour the gelée into the prepared pan. Freeze until firm before adding crémeux, about 1 hour.

For the ruby raspberry crémeux:

Bloom the gelatin: Combine the gelatin and 15g of the heavy cream in a small bowl. Stir with a spoon until the gelatin has dissolved. Allow to bloom for 5-10 minutes.

Make the crémeux: Place the chopped ruby chocolate in a medium heat-safe bowl and set a fine-meshed sieve over it.

Place egg yolk in a medium bowl. Heat the corn syrup in the microwave until warm. Slowly whisk into the egg yolk until smooth (warming the corn syrup helps temper the yolk).

In a small saucepan, combine the remaining 120g heavy cream and whole milk. Bring to a simmer over medium heat.

Once the cream-milk mixture comes to a simmer, slowly whisk into the egg yolk mixture until well incorporated. Scrape the mixture back into the saucepan. Cook over medium heat, whisking constantly, until the mixture reaches 180F on a digital thermometer. Remove from heat, then add bloomed gelatin and whisk to combine thoroughly. Strain mixture over the chocolate. Let sit for one minute, then whisk together to form a smooth emulsion. Add the raspberry puree and whisk in thoroughly.

Freeze the crémeux: Pour crémeux over set raspberry gelée. Freeze uncovered until top is set, about 1 hour. Press a piece of plastic wrap on top and freeze until completely solid, at least 5 hours or overnight.

For the chocolate crumb:

Preheat the oven to 300F. Line a baking sheet with parchment paper or a silicone mat.

In a medium bowl, whisk together the flour, cornstarch, sugar, cocoa powder, and salt until well combined. Add the melted butter and stir until the mixture forms small clusters.

Spread the clusters in one layer on the prepared baking sheet. (I like to squeeze some clumps together to get a mixture of bigger and smaller pieces.) Bake for 20-22 minutes, stirring occasionally to promote even baking. The clumps should be slightly moist to the touch; they will harden as they cool.

Let crumbs cool completely, then transfer to an airtight container. Store at room temperature for up to a week, or in the freezer for up to a month.

For the dark chocolate raspberry mousse:

Note: prepare the mousse right before assembling the cake.

Combine the gelatin and 35g whole milk in a small bowl. Stir until the gelatin has dissolved. Set aside to bloom for 5-10 minutes.

Place the chopped dark chocolate in a medium bowl and set a fine-meshed sieve over it.

Put the remaining 147g milk in a small saucepan. Heat over medium heat until steaming, stirring occasionally. Once steaming, remove from heat and whisk in the bloomed gelatin mixture.

Strain over the chopped chocolate. Let mixture sit, without stirring, for 30 seconds; then whisk until the chocolate has melted and the mixture is smooth. Add the raspberry puree and whisk until completel.ombined. Let cool at room temperature while you whip the cream (you want the ganache to be slightly warm when combining with the cream).

Place the cold heavy cream in a large bowl (or in the bowl of a stand mixture fitted with the whisk attachment). Whisk on medium speed until soft peaks form.

Slowly pour the ganache into the whipped cream a little at a time, gently folding it in with a spatula until just combined. Transfer to a piping bag and use immediately.

Assemble the chocolate raspberry mousse cake:

Note: I recommend preparing the cake ring and trimming the layers before making the dark chocolate raspberry mousse.

Line the inside of a 6×3 cake ring with acetate and set on a plastic-lined sheet pan. Make sure you have space in your freezer where the sheet pan can fit flat so the cake can freeze properly.

Trim the cake and gelée-crémeux rounds so both are about 1/4″ to 1/2″ smaller than the cake ring (5 1/2″ to 5 3/4″ inches in diameter). Trim the cake to about 1/2″ thickness. (Save leftovers for snacking or another project, or see baker’s notes for thoughts on using more cake layers.)

Prepare the dark chocolate raspberry mousse (see above).

Pipe about 1/2″ of mousse into the bottom of the cake ring. Lightly tap the pan to ensure there are no air bubbles and smooth the top with an offset spatula. Set the cake layer on top of the mousse and gently press into the mousse until the mousse comes over the edge of the cake a bit. Pipe in about 3/4″ layer of mousse into the cake ring covering the cake layer. Set the gelée-crémeux layer on top of the mousse, gelée side on top. Gently press into the mousse until the mousse comes up the edge of the crémeux. Pipe mousse around the edge of the gelée-crémeux, then pipe in mousse to fill the remainder of the mold. Tap pan again to remove any air bubbles. Smooth the top so it is perfectly flush with the top of the mold. (You may have a little mousse leftover — consider it a baker’s treat!)

Transfer the sheet pan to the freezer. Freeze until solid, at least 3 hours or overnight.

Make the dark chocolate glaze:

Note: prepare glaze about 1-2 hours before you want to glaze the cake, or at least 3-4 hours before serving. After glazing the cake will still need fully defrost in the fridge before serving.

Combine the gelatin and 60g cold water in a medium bowl. Stir until the gelatin has dissolved. Set aside to bloom for 5-10 minutes.

Sift the cocoa powder into a medium saucepan. Add the 75g room temperature water and stir to form a thick paste. Add a small amount of cream and whisk to loosen. Add the remaining cream and sugar and whisk to combine.

Bring to a simmer over medium heat, whisking until the sugar has dissolved. Cook, whisking occasionally, until the glaze just comes to a boil, about 3-5 minutes.

Set a fine-meshed sieve over the bloomed gelatin and pour the glaze through the sieve. Whisk to combine and melt the gelatin. Blend with an immersion blender to remove lumps and air bubbles. Press a piece of plastic wrap against the surface and cool to 95F before glazing the cake (this took me about an hour). Right before glazing, strain glaze again into a tall pouring container to remove any air bubbles — pour from a low distance for best results. (Note: glaze can be stored in an airtight container for up to a week; rewarm in the microwave to 95F before using.)

Glaze the mousse cake:

At least 3 hours before serving, unmold and glaze the cake. Line a sheet pan with plastic wrap and set a sturdy plastic container or 4″ cake pan on top. (You want something smaller than the diameter of the cake so the glaze will drip off properly, but make sure it’s level and sturdy.) Take the cake out of the freezer and remove the cake ring. Move the cake to a 6″ cake board and remove the acetate. Double check the glaze is at working temperature — at 95F — before glazing. If not, wrap cake tightly in plastic and keep in freezer until ready to glaze — the cake must be frozen and not starting to melt when the glaze is applied.

In one swift and confident motion, pour most of the glaze over the center of the cake. If everything is at the proper temperature, the glaze should flow down and cling to the sides of the cake. If there are any spots that get missed, use an offset spatula to gently smear some extra glaze on. Let set for a couple of minutes, then use an offset spatula to cut off any stray drips at the base of the cake.

Finish and serve the mousse cake

Use a cake lifter or a couple of offset spatulas to move the glazed cake onto a serving plate. (The extra glaze can be refrigerated in an airtight container for up to a week or frozen; rewarm before using.) Decorate with chocolate crumbs at this point if desired (they will adhere better when the glaze is still a little sticky). Transfer cake to the refrigerator to thaw completely before serving (at least 2 hours, or up to a couple days). Decorate with edible glitter paint, and fresh raspberries (brushed with some warmed apricot jam for shine), if desired, before serving.

chocolate raspberry mousse cake slice

Related recipes and resources:

Mango Charlotte Cake

Do you have a cooking or baking bucket list? On my ever-growing one is gourmet pasta, multiple types of dim sum, and French entremets. Admittedly most of the things left on my list are a tad complicated and/or time consuming, so I’ve resigned myself to the reality that I probably won’t get to them for another decade or so (i.e. when the littles are more self-sufficient, at least).

While 7-layer entremets may have to wait, I’ve been able to tackle a couple other “fancy” cakes that are a little less complicated. The latest was this mango charlotte, which featured alternating layers of sponge cake and mango mousse surrounded by ladyfingers and topped with a mango glaze. The result was a beautifully light, sophisticated cake bursting with mango flavor. I’m eager to try this again with different fruits (raspberries? blackberries?); as it is definitely a nice alternative to a typical American-style layer cake.

Most charlottes call for a classic genoise as the cake portion. I used a Japanese genoise, which is a little sweeter and more m-m-moist than its European counterpart. To be honest, sponge cakes aren’t my forte but I’ve had good success with this one. The keys, I’ve found, are to whisk the eggs for a long time on a low speed (to build structure) and to fold in the flour with a slotted spoon (it’s faster and more efficient than a spatula). I tend to err on the side of undermixing, but don’t be like me unless you want failed batches of genoise with a) rubbery bottoms (from not mixing in the fats evenly) or b) flour bits (self-explanatory).

The star of the show is the fruit, though; I think I used about 7 medium-sized whole mangoes to make this cake! So you really do need to find very ripe, flavorful mangoes for this cake. Look for ones that have a little give when you gently squeeze them; and smell strongly of mango when you give them a sniff. If anything, err on the side of over-ripe!

While the mousse and glaze should be prepared right before using, the cake and ladyfingers can be baked in advance (freeze if you’re not using the same day). If you’re pressed for time, store-bought ladyfingers will do just fine as well.

Mango Charlotte Cake

Makes one 9-inch cake

Ingredients

For the ladyfingers
Makes about 3 dozen; freeze the extras or snack on them! | Adapted from The Cake Bible

  • 6 large eggs, separated
  • 150g caster sugar
  • 10g vanilla
  • 1 T warm water
  • 150g sifted cake flour
  • 3/4 tsp cream of tartar
  • Icing sugar, for sifting

For the Japanese Genoise
Adapted from Natalie Eng

  • 173g cake flour, sifted
  • 255g eggs (approx. 5 large), at room temperature
  • 195g caster sugar
  • 23g glucose
  • 45g unsalted butter
  • 68g whole milk
  • 1 1/2 tsp pure vanilla extract

For the Mango Mousse
Adapted from Joe Pastry

  • 567g (20 oz., about 4 medium-large) ripe fresh mangoes, cut into chunks (note: you will need additional mango (some pureed, some cut into chunks for the mirror glaze and filling; I recommend cutting up a couple extra mangoes and setting aside for that purpose)
  • 85g sugar
  • 2 Tbsp. fresh lemon juice
  • 3 1/2 tsp. powdered gelatin
  • 2 c heavy cream, chilled

For the Mango Mirror Glaze
Adapted from The Little Epicurean

  • 57g mango puree
  • 57g water
  • 28g sugar
  • 1 1/2 gelatin sheets (silver strength), bloomed

To assemble

  • 2 to 2 1/2 dozen ladyfingers (4-inch tall), bottoms trimmed
  • Simple syrup
  • ~1 c fresh mango chunks
  • Fresh berries for garnish (optional)
  • White chocolate curls for garnish (optional)
  • 9×3 cake ring (or springform pan)
  • 9-inch cake board
  • Acetate (can also use parchment paper or plastic wrap)

Method

Make the ladyfingers

  1. Preheat the oven to 400F. Line two large baking sheets with parchment paper (you may need 3 if your pans are small).
  2. In a large mixing bowl, beat the yolks and 1/2 c sugar on high for 5 minutes, or until the mixture is very thick and ribbons when dropped from the beater. Lower the speed and beat in the vanilla and water. Increase the speed to high and beat for another 30 seconds, or until thick again. Sift the flour over the yolk mixture without mixing in and set aside
    In another large bowl, beat the whites until foamy. Add the cream of tartar, and beat until soft peaks. Gradually beat in the remaining 1/4 c sugar, beating until very stiff peaks.
  3. Add 1/3 of the whites to the yolk mixture and use a slotted spoon or spatula to fold until all the flour is incorporated. Gently fold in the remaining whites.
  4. Transfer some of the batter to a piping bag fitted with a large round tip. Pipe 4 inch lines (“fingers”), leaving about 1/4 inch between each. (They will bake into each other, forming continuous strips.) Continue piping until you have used all the batter.
  5. Sift powdered sugar completely over the fingers. Once the sugar has dissolved, sift a second coat on.
  6. Bake for 8-10 minutes, or until light golden brown and springy to the touch. Transfer to a wire rack to cool slightly. Remove from the sheets while still a little warm (to prevent cracking) using a long, thin spatula or pancake turner. Cool completely on racks before using or store in an airtight container. (Note: If you aren’t using that day, I recommend freezing the fingers for longer storage as they do stale. They defrost quickly, so just pull them out about an hour before you want to assemble the cake.)

Make the Japanese Genoise Cake

  1. Preheat the oven to 350F. Line the bottoms of two 8-inch cake pans with parchment paper. Grease and flour the pans and set aside.
  2. In the bowl of a stand mixer, heat the eggs, sugar and glucose, whisking constantly, over a bain marie until the mixture reaches 45-50C. Transfer the bowl to the stand mixer and mix on high speed until pale and fluffy. Reduce the speed to low and keep whisking for an additional 7 minutes. This allows the air bubbles to be even and small hence making it more stable so you will not knock so much air out when you fold in the flour.
  3. In a saucepan (or in the microwave), heat the milk, butter and vanilla essence until the butter has melted and the mixture is warm. Mix about 1 cup of the egg mixture into the butter mixture and whisk to combine. Set aside.
  4. Sift the flour in three parts into the egg mixture, folding each part in with a large slotted spoon (my preferred tool) or a silicone spatula before adding more flour. You want to fold gently but also ensure the flour is completely mixed in; otherwise you will have lumps in your cake. Once the flour is well incorporated, pour the butter mixture into the egg batter and fold it in until it is well incorporated. Do not overmix, but again make sure the butter mixture is well incorporated; otherwise the bottom of your cake will be rubbery. The batter should still be fluffy and almost as if it’s heaving.
  5. Divide the batter evenly between the prepared pans and bake for about 25 minutes, or until golden brown on top, the cake springs back when lightly pressed, and the cake is pulling away from the sides of the pan. Rotate the pans after about 20 minutes for even baking (don’t open the oven sooner or your cakes may collapse). Transfer the finished cakes to a wire rack. Cool for about 10 minutes in the pan; then turn the cakes out and finish cooling them completely on the rack.

Prepare the cake pan

  • Line your cake ring with acetate and place a cake board on the bottom. Trim the tops and bottoms of the cakes. Place one cake round in the center of the cake ring and brush liberally with simple syrup. Place the ladyfingers around the edge, fitting them in tightly to ensure there are no gaps (you may have to trim the edge of the last one to fit neatly). Set aside while you prepare the mousse.

Make the Mango Mousse

  1. Whip the cream to soft peaks and keep refrigerated until ready to use.
  2. Combine the mango chunks, sugar, and lemon juice in a food processor and process until smooth. Strain the mixture through a sieve into a medium bowl. You should have ~2 cups of puree.
  3. Heat about one third of the mixture in a small saucepan or in the microwave until warm but not boiling. Sprinkle the gelatin evenly over the surface and stir to combine completely. Stir the warmed mixture back into the rest of the puree. Cool the mixture back to room temperature, stirring occasionally. When the mango is cooled, whip the cream to stiff peaks. Gently but thoroughly fold the mango mixture into the cream. Use immediately.

Continue assembling the cake

  • Evenly spread about a cup of mousse over the first cake layer, making sure to go right to the edges. Sprinkle the mango chunks evenly over the mousse. Spread on another ~1/2 cup of mousse (or enough to cover the mango chunks). Place the second cake layer on top and press down to ensure it’s level. Brush liberally with simple syrup. Evenly spread on another cup of mousse, leaving about an inch from the top for the mirror glaze and garnish. Refrigerate until mousse is set, at least 4 hours or overnight.

Make the Mango Mirror Glaze

  • Heat the water, sugar, and puree in a small saucepan until warm but not boiling. Remove from heat and immediately stir in the bloomed gelatin. Transfer mixture to a glass measuring cup (preferably with a spout for easy pouring) and cool until just slightly warm, stirring occasionally. Use immediately.

Glaze and finish cake

  1. Remove the chilled cake from the fridge. Pour the glaze evenly over the top of the cake. Return the cake to the fridge to set completely (about 1/2 an hour).
  2. Remove the cake ring and acetate. Garnish top with fresh berries and white chocolate curls, if desired. Refrigerate until ready to serve.