Fudgy Mocha Cake with Raspberry Mousse, Chocolate Ganache, & Raspberry Swiss Meringue Buttercream

I got up early for this one!

I got up early for this one!

Pumpkin, this one’s for you!

I feel like the luckiest baker in the world right now, because as I write this, I am taking occasional bites out of a slice of this very beast. It’s a winner, for sure: fudgy, moist, intensely dark chocolate cake layers are filled with raspberry mousse, iced with milk chocolate ganache, and decorated with raspberry Swiss meringue buttercream icing. I decided to do a raspberry riff on this incredible caramel and chocolate beauty, and oh. My. Word. This is a raspberry and chocolate lover’s dream. No other raspberry and chocolate dessert I’ve ever had comes even close to being this good.

Zing! Pow! Whee!

Zing! Pow! Whee!

Nonetheless, I think it could have been better. I tried using Sugar Hero‘s raspberry mousse recipe, with several tweaks of my own, because hers incorporates white chocolate into the mousse, and I figured the white chocolate would give the mousse more structural stability. The cake has three layers, after all, so I thought that that much cake weighing on that much mousse would require a little extra help. Well, the mousse is stable enough to withstand being layered this way, but it also has a weird note of white chocolate running through it that I actually don’t care for. This weird flavour note diminished by as soon as the next day, and now, two days later, is virtually gone, but it was unpleasant enough that first day to make me want to try a different raspberry mousse recipe next time. I have one that I adore, and I should have used that one. It’s a bit soft, but I think adding a little more gelatin would make it good and firm. I’m including the recipe for the mousse I used in this version of the cake, so you at least have the option of trying it out.

You can really see the lovely, moist texture of this cake here. I love this cake recipe!

You can really see the lovely, moist texture of this cake here. I love this cake recipe!

The second way this cake could have been better was by using less coffee in the cake batter! I know, I know; I never thought I’d say anything of the sort, but these things happen to the best of us. The cake was so dark chocolate-y – and this can be a good thing, depending on your personal preferences – that it made the raspberry mousse taste almost bland in comparison. When allowed to stand at room temperature for about an hour, this flavour differential diminished notably, but I strongly recommend using only 1/4 cup coffee for this version of this cake. (I’ve made it several times before, because it’s probably my favourite chocolate cake recipe at this point.) That little coffee would boost the chocolate flavour without making it so dark, and the raspberry flavours would brighten quite a bit against this chocolate backdrop. Again, if really dark chocolate cake is your thing, then use 1 1/4 cups coffee in the cake recipe. You’ll have a dark chocolate lover’s dream. 🙂

Dragées 4 Life. Or something. I never got into the whole yearbook shorthand.

Dragées 4 Life. Or something. I never got into the whole yearbook shorthand.

As this cake was for a very special occasion, I put on my hat and went out to buy some silver dragées. In Europe, these are seen as harmless bits of sugary decoration, meant to be consumed only on special occasions, but here in the States, the FDA has ruled that we’re not supposed to eat them, not even on special occasions, because of the small amounts of silver they contain. We have trace amounts of silver in our persons, anyway, and eating a silver dragée now and again is not going to harm you. (Unless you have a silver allergy, in which case this advice is very, very bad.) So I ate some. 🙂

That cake slice is... lurking.

That cake slice is… lurking.

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Fudgy Mocha Cake with Raspberry Mousse, Chocolate Ganache, & Raspberry Swiss Meringue Buttercream

Yield: One three-layered, 8″ cake


For the cake:
1¾ cups plus 2 TBS all-purpose flour
1¼ tsp baking soda
¾ tsp salt
1½ cups unsweetened cocoa powder, plus more for dusting pans (unless spraying pans with nonstick spray such as Baker’s Joy)
1¼ cups espresso/strong coffee + ¼ cup water; OR ¼ cup espresso/strong coffee + 1¼ cups water; OR 1½ cups water + 3 TBS instant espresso powder (you should have 1½ cups liquid, total)
¾ cup sour cream
1 TBS vanilla extract
3 sticks unsalted butter, at room temperature
2½ cups plus 2 TBS sugar
3 large eggs, at room temperature

For the raspberry mousse:
1 envelope unflavoured gelatin (about 2 tsp.)
¼ cup cold water
8 – 10 oz. fresh (washed and dried) or frozen raspberries, to yield ½ cup strained raspberry purée (you should have ½ cup after straining)
11 oz. white chocolate, chopped
1 tsp. raspberry extract
1¾ cups heavy cream, divided
pink food colouring (optional)

For the chocolate ganache:
16 oz. milk chocolate
½ stick unsalted butter, cut into 4 pieces
1 1/3 cups heavy cream

For the raspberry Swiss meringue buttercream:
5 egg whites
1¼ cups sugar
3 sticks unsalted butter, at room temperature & cut into 1″ cubes
1 tsp. raspberry extract
8 – 10 oz. fresh (washed and dried) or frozen raspberries, to yield ½ cup strained raspberry purée (you should have ½ cup after straining)
pink food colouring (optional)
silver dragées, for garnish (optional)


For the cake:
Preheat oven to 350˚F. Spray 3 8″ round cake pans* with Baker’s Joy or similar and line the bottoms of the pans with parchment paper; spray the parchment paper. Alternatively, butter the insides of the pans and dust with cocoa powder, shaking out the excess, and line the pans with parchment paper. Note: I highly recommend lining the pans with parchment paper, as the cakes tend very much to resist coming out of the cake pans.

In a medium bowl, combine the flour, baking soda, and salt. Stir with a fork or whisk to blend and set aside.

Combine espresso and water. The mixture should measure 1½ cups. Heat mixture to boiling in microwave. In a medium bowl, combine the cocoa powder and espresso mixture (or combine the cocoa powder, 1½ cups boiling water, and 3 TBS instant espresso powder). Whisk until smooth; set aside to cool slightly. When cooled down a bit, whisk in the sour cream and vanilla until smooth. Set aside.

In the bowl of an electric mixer, beat the butter on medium-high speed until smooth, about 1 minute. Gradually blend in the sugar and whip on medium-high speed until light and fluffy, 2 – 3 minutes more. Blend in the eggs one at a time, scraping bowl after each addition.

With the mixer on low speed, add the dry ingredients and the sour cream mixture alternately, beginning and ending with the flour mixture and beating each addition just until incorporated.

Divide the batter evenly between the prepared pans.* Bake the cake layers for about 30 – 32 minutes or until a toothpick inserted in the center comes out clean, rotating the pans during halfway through to ensure even baking. Transfer the baked cake layers to a wire rack and let cool in the pans at least 10 minutes before inverting onto the rack to cool completely.

Once the cake is made and cooled, place the first layer onto a serving platter and surround with an 8″ springform pan ring. (Place the other two layers in a safe place until you’ve made the mousse and are ready to fill the cake.) Form a waxed or parchment paper collar (you can see a parchment paper collar in the assembly photos in the Chocolate Stampede Cake post) around this cake layer and close the springform pan ring. Set aside.

For the mousse:
Once the cake is baked and cooled, and the bottom cake layer is resting in its paper collar, make the mousse. Pour the cold water into a small bowl and sprinkle the gelatin on top. Whisk well with a fork and set aside. Purée the raspberries* and strain the purée; discard the pulp and seeds. Transfer the strained liquid to a 2 quart saucepan, along with the white chocolate and ½ cup of the heavy cream. (Refrigerate the remainder of the cream until needed.) Cook on medium-low heat, stirring frequently, until the white chocolate is melted and thoroughly blended with the raspberry liquid. Remove from heat and add raspberry extract and food colouring, if using. Whisk in the gelatin/water mixture (it may be in small clumps; keep whisking until all is smooth). While the resultant mixture is cooling, whip the remaining heavy cream just until stiff peaks form. Once the raspberry mixture is completely cooled, fold it into the whipped cream.

Spread half the raspberry mousse onto the bottom cake layer, ensuring the mousse layer is even. (A long-handled spatula or wooden spoon is good for this.) Top with one of the remaining two cake layers and spread with the rest of the mousse, ensuring that this mousse layer, too, is even. Top with last cake layer.

Refrigerate cake for 4 – 6 hours to ensure the mousse is firm.

For the chocolate ganache:
While the mousse is firming, make the chocolate ganache. Place chocolate and butter into a large heat-proof bowl. Heat the cream to boiling and immediately pour over the chocolate and butter. Allow to stand for 2 – 3 minutes, then whisk until all ingredients are completely blended and smooth. Cover loosely with aluminum foil and let sit for several hours, until it is firm enough for icing.

Once the cake has been refrigerated for 4 – 6 hours, and the ganache is firm enough to use for icing, remove the springform ring. Carefully peel away the paper collar. Ice the cake with the ganache and return cake to the refrigerator. Refrigerate 6 – 8 hours to ensure all components are firm; overnight is best.

For the raspberry Swiss meringue buttercream:
Once the ganache-iced cake has chilled thoroughly, make the Swiss meringue buttercream. Purée the raspberries* and strain the purée; discard the pulp and seeds. Set the strained liquid aside.

Heat the egg whites and sugar, whisking constantly, in a heatproof bowl set atop a saucepan of simmering water until the mixture reaches 160˚F on a candy thermometer and the sugar is completely dissolved. Immediately transfer the contents of the bowl to the bowl of a stand mixer (I always just cook the egg whites in the stand mixer bowl, as this is more efficient) and, using the whisk attachment, whisk on medium-high speed until stiff peaks form and the bowl is cool to the touch. Reduce speed to medium and add the softened butter, 2 – 3 pieces at a time, waiting until each of the pieces has been incorporated before adding more butter. Once all the butter has been added, increase speed to medium-high and beat until the mixture is completely creamy and smooth. If the mixture looks curdled or soupy, don’t worry – this is completely normal with Swiss meringue buttercream. Just increase speed to high and keep on whipping until it comes together. This may take up to 45 minutes, but it will come together.

Once the buttercream is completely smooth and thick and creamy, lower mixer speed to medium-low and add the raspberry extract. Still on medium-low speed, stream in the raspberry purée and whip until completely blended. Blend in food colouring, if using.

Pipe decorative swirls around the top and bottom of the cake, or just use the buttercream to ice around the outside of the cake in whatever way you wish.** Stud cake with silver dragées, if desired.

Cake should be stored in the refrigerator and sliced with a hot, dry knife. Allow slices to sit at room temperature for an hour before eating, to ensure best texture and flavour.

*If using frozen raspberries, you will need to heat them on medium-low heat in a 1 quart saucepan, stirring occasionally, so that they can be squished and strained. Use a wooden spoon to crush the berries as they thaw, and strain the resultant purée. Set aside to cool completely.

**I had leftover buttercream, so it is likely you will, too. I was thrilled to learn that Swiss meringue buttercream can be frozen for up to 3 months; simply allow to thaw at room temperature, and re-whip to regain creamy consistency. I haven’t personally tested this, but I have high hopes. 🙂

Sources: Ganache from, and cake slightly adapted from, Annie’s Eats; raspberry mousse moderately adapted from Sugar Hero; raspberry Swiss meringue buttercream slightly adapted from Sweetapolita


One thought on “Fudgy Mocha Cake with Raspberry Mousse, Chocolate Ganache, & Raspberry Swiss Meringue Buttercream


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