Craving an exceptionally decadent dessert? Then it has to include mousse! There are so many delicious ways to enjoy mousse, but chocolate mousse cake—layers of decadent chocolate cake and rich mousse—has to be one of the best.
Follow along as we show you how to bake and build the cake, and read up on our tips for making it your own.
Chocolate Mousse Cake Ingredients
Cake:
- Butter, softened
- Sugar
- Egg
- Vanilla extract
- Buttermilk
- Sour cream
- All-purpose flour
- Baking cocoa
- Baking soda
- Salt
Chocolate mousse filling:
- Semisweet chocolate, chopped
- Heavy whipping cream
- Vanilla extract
Ganache:
- Semisweet chocolate, chopped
- Butter, cubed
- Heavy whipping cream
Directions
Step 1: Make the cake batter
This chocolate mousse cake starts with butter and sugar. Cream them together in the bowl of a stand mixer for five to seven minutes until light and fluffy. Then beat in the egg and vanilla extract.
While those ingredients are whizzing away in the mixer, stir the sour cream and buttermilk together in a small dish. These ingredients help make an extra tender cake. In another bowl, whisk together the flour, cocoa powder, baking soda and salt. Then alternate adding the dry ingredients and the buttermilk-sour cream to your mixing bowl. Be sure to beat well after each addition.
Step 2: Bake the cakes
Next, grease and line two 8-inch cake round cake pans. Divide the batter evenly between both pans. Then bake at 350ºF for 30 to 35 minutes or until a toothpick inserted in the center comes away with a few crumbs. Remove the cakes from the oven and let them cool for 10 minutes. Then turn the cakes out onto wire racks to cool completely.
Step 3: Make the mousse filling
As the cakes are baking and cooling, you can start making the star of the show: the chocolate mousse! Start the mousse by melting the chocolate and cream together on low heat. Don’t rush this process or be tempted to crank up the heat. Low and slow is the best way to melt chocolate over the stove.
Once fully melted, remove from the heat and stir in the vanilla extract. Transfer the mixture to a bowl and chill until slightly thickened. Pop into the fridge on occasion to give it a stir. This will help you keep an eye on the chocolate as it thickens.
Once cooled and thickened, beat the chocolate on medium speed until it gets light and fluffy. Return the mousse to the fridge until it achieves spreading consistency.
Step 4: Make the ganache
Besides being full of lush chocolate mousse, this cake is topped with decadent ganache. To make the ganache icing, start by heating chocolate and butter together in a saucepan until melted. Again, do this on low heat and take your time. Once melted, slowly add the cream and heat until warmed. Transfer the ganache to a bowl and chill until it’s spreadable like frosting.
Step 5: Layer and frost the cake
To transform the two cake layers into four, grab a serrated bread knife. Very carefully slice the layers in half with a gentle sawing motion, much like you’d tort a cake.
Place the first layer of cake onto a cake stand or cake plate. Then evenly spread a third of the chocolate mousse over the top. Repeat with the remaining layers of cake and mousse.
All that’s left is to frost the outside of the cake with the creamy chocolate ganache. The spreadable ganache works similarly to buttercream frosting. Use an offset spatula and take your time making a smooth and appealing finish.
Editor’s Tip:Â If your mousse or ganache has firmed up too much in the fridge, let it sit at room temperature until it reaches a spreadable consistency. Don’t microwave! Let time and room temperature do their work.
Chocolate Mousse Cake Variations
There are so many fun ways to customize a chocolate mousse cakes to suit your tastes—both for flavor and aesthetics:
- Pump up the flavor: Try adding a bit of orange liqueur like in this Julia Child mousse recipe. You can also add a touch of mint extract (use this sparingly!). If you want to add some crunch, sprinkle toasted nuts between the layers or over the top of the cake.
- Add decorations:Â Our Test Kitchen kept the decoration on this cake simple, but that doesn’t mean you have to! Use buttercream and try your hand at piping a message or flowers on top. Sprinkles are always welcome on top of a cake.
- Try it naked:Â You read that right! But we mean naked in the cake sense. Naked cakes allow you to get a peek at all the decadent filling inside a cake. What better way to show off the lush chocolate mousse inside this layer cake?
Chocolate Mousse Cake Tips
Can you make chocolate mousse cake ahead of time?
You can make chocolate mousse cake in advance, but not very far, ahead. For the best texture and flavor, make the cake only a day before your event.
How do you store chocolate mousse cake?
Be sure to store the cake in the refrigerator. Before serving, take the cake out of the fridge and let it sit at room temperature for about 45 minutes. This allows the mousse and ganache to get back to their creamy, rich textures.
