Chocolate Mousse Cake
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Right after Mother’s Day, we celebrated my husband’s birthday, and I knew there was only one dessert that would make him truly happy—a chocolate cake. Chocolate is his absolute favorite, so I wanted to make something extra special. Since I had leftover chocolate mousse from my Mother’s Day crepes, I decided to turn it into a decadent chocolate mousse cake, layers of chocolate cake with creamy mousse and smooth buttercream frosting.
The result? A tasty, crowd-pleasing dessert that was a huge hit with my husband and the whole family! It’s a chocolate lover’s dream! The best part is that you can use any moist chocolate cake layers as the base—whether homemade or store-bought. I kept it simple by using a boxed cake mix for the chocolate cake base, which made the process easy while still delivering an impressive, bakery-style dessert. This cake is proof that you don’t need complicated techniques to create something beautiful, delicious, and celebration-worthy!
Ingredients for Chocolate Mousse Cake
- 2 PREPARED 8″ OR 9″ ROUND CHOCOLATE CAKES (I JUST USED A BETTY CROCKER CHOCOLATE FUDGE CAKE)
- UNFLAVORED GELATIN
- COLD WATER
- BOILING WATER
- SUGAR
- HERSHEY’S COCOA
- COLD HEAVY CREAM
- VANILLA EXTRACT
- BUTTER
- SALT
- POWDERED SUGAR
- MILK
Instructions for Easy Chocolate Mousse Cake Recipe
Make the Chocolate Cake: I just baked a Betty Crocker Triple Fudge Cake according to the package instructions. Then pour the cake batter into two 9-inch round cake pans and cook according to the package for those size pans. For easy removal, I line the bottom of the pans with parchment paper. Allow to cool on a wire rack.
Make the Chocolate Mousse: In a small cup, sprinkle gelatin over cold water and let it sit for 1 minute to soften. Add boiling water and stir until the gelatin is completely dissolved. Let it cool slightly. In a medium bowl, mix sugar and cocoa powder, then add whipping cream and vanilla extract. Beat on medium speed until the mixture forms stiff peaks, scraping the bottom of the bowl occasionally. Pour in the gelatin mixture and beat until fully blended. Store the mousse in the refrigerator while preparing the frosting.
Make the Chocolate Buttercream Frosting: In a mixing bowl, beat butter, cocoa powder, and vanilla extract on medium speed until creamy. In a separate bowl, whisk together powdered sugar and cocoa powder. Gradually add the powdered sugar mixture to the butter mixture, alternating with 3 tablespoons of milk, 1 tablespoon at a time, beating at low speed until smooth. If needed, beat in up to 4 additional tablespoons of milk to reach your desired frosting consistency.
Assemble the Cake: Place one cake layer on a serving plate and spread the chocolate mousse evenly over the top using an offset spatula. I like to top it with 2/3 of the mousse mixture. Carefully place the second cake layer on top. Then I use the remaining mousse mixture to fill in the sides so it is even with the sides of the cake.
Frost the entire cake with chocolate buttercream frosting, being gentle around the mousse layer to prevent mixing. Refrigerate the cake until ready to serve. For best texture, let it sit at room temperature for a few minutes before serving to soften the frosting.
Frequently Asked Questions
Can I make the mousse ahead of time?
Yes! You can prepare the mousse up to 24 hours in advance and store it in the refrigerator until you’re ready to assemble the cake.
How do I prevent the mousse from mixing into the frosting?
When frosting the cake, gently spread the buttercream over the mousse layer without pressing too hard. Using a piping bag to apply frosting around the edges first can help create a clean barrier.
How long should I refrigerate the cake before serving?
Keep the cake in the refrigerator until ready to serve, but let it sit at room temperature for 15-20 minutes before slicing to soften the frosting.
Can I freeze this cake?
Yes! You can freeze the assembled cake for up to 3 months. Wrap it tightly in plastic wrap and store it in an airtight container. Thaw in the fridge overnight before serving.
What toppings go well with this cake?
Try garnishing with chocolate shavings, fresh berries, whipped cream, or a dusting of cocoa powder for an elegant touch.
FOR MORE RECIPES LIKE THIS, TRY:
- Chocolate Oreo Cream Cake
- One Bowl Chocolate Cake
- The Perfect Chocolate Cake
- Moist Chocolate Cupcakes with Chocolate Buttercream
Chocolate Mousse Cake
Real Mom Kitchen
Equipment
Ingredients
Cake:
- 2 prepared 8″ or 9″ round chocolate cakes I just used a Betty Crocker Chocolate Fudge cake
Chocolate Mousse:
- 2 tsp unflavored gelatin
- 2 Tbsp cold water
- 4 Tbsp boiling water
- 1 cup sugar
- ½ cup HERSHEY’S Cocoa
- 2 cup cold whipping cream
- 2 tsp vanilla extract
Frosting:
- ¾ cup butter softened
- 1 ½ tsp vanilla extract
- ⅛ teaspoon salt
- 6 cups powdered sugar
- 1 cup HERSHEY’S Cocoa
- 7 Tbsp milk
Instructions
- To make the mousse: Sprinkle gelatin over cold water in small cup; let stand 1 minute to soften. Add boiling water; stir until gelatin is completely dissolved. Cool slightly.
- Stir together sugar and cocoa in medium bowl; add whipping cream and vanilla. Beat on medium speed of mixer, scraping bottom of bowl occasionally, until mixture is stiff. Pour in gelatin mixture; beat until well blended. Store in the refrigerator while you make the frosting.
- To make the frosting: Beat first 3 ingredients at medium speed with an electric mixer until creamy.
- Whisk together powdered sugar and cocoa. Gradually add powdered sugar mixture alternately with 3 Tbsp. milk, 1 Tbsp. at a time, beating at low speed until blended and smooth after each addition. Beat in up to 4 Tbsp. additional milk for desired consistency.
- To make the cake: Place one of the round cakes on your serving plate and top with chocolate mousse. Top with remaining cake round and frost entire cake with chocolate buttercream frosting. Be careful at the spots where the chocolate mousse is. You need to get the frosting to just cover those spots, if you spread to much in those areas the chocolate mousse can get mixed into the frosting. Keep cake in the refrigerator until ready to serve. You can bring it out a little before serving to allow the frosting to soften.
