This moist and rich chocolate mousse cake is layered with thin layers of dark chocolate cake and a light and creamy chocolate mousse, then coated with chocolate ganache for the ultimate decadent chocolate dessert.
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Why This Recipe Works
If you're looking for an indulgent special occasion dessert for Valentine's Day, Christmas, a birthday, or just a random Tuesday, this is it! It's got chocolate cake layered with chocolate mousse, and then all coated in a silky smooth chocolate ganache. It doesn't get much better than that! I'll show you how to make all three components yourself, but you can totally use a boxed cake mix for the cake if you want.
How to Make the Chocolate Cake
This rich and moist chocolate cake is really simple to make in just a few easy steps.
- Preheat your oven to 350°F. Prepare two 8 inch round cake pans with non-stick baking spray or grease and flour.
- Add the sugar, flour, cocoa powder, espresso powder, baking powder, baking soda and salt to a large mixing bowl and whisk to combine.
- Add the eggs, milk, oil and vanilla to the dry mixture and mix with an electric hand mixer, starting on low and gradually increasing to medium speed for 1 to 2 minutes until smooth. Set the mixer speed to low and slowly pour in the boiling water (or hot coffee). Mix on low until just combined.
- Divide the batter between the pans and bake for about 35 minutes, until a toothpick inserted into the middle comes out clean. Let the cakes cool completely in the pan.
Make Ahead: The chocolate cakes can be made up to 2 days ahead. Allow the cakes to completely cool. Then individually wrap tightly in plastic wrap and refrigerate.
How to Make the Chocolate Mousse
This easy chocolate mousse combines homemade whipped cream, melted chocolate, and bloomed cocoa powder to add a creamy layer between the cake layers.
- To make the mousse, add the hot water to your cocoa powder in a medium bowl and whisk to combine, then set aside.
- Melt the chopped chocolate bars in a double boiler or carefully in the microwave in 15-20 second increments, stirring between each one, until melted. Pour in the reserved cocoa mixture and stir to combine, then set aside.
- In a stand mixer fitted with a whisk attachment add the heavy whipping cream, powdered sugar, and vanilla and mix on medium-high speed until peaks form.
- Using a rubber spatula, scrape the chocolate mixture into the whipped cream and gently fold to combine. Cover and refrigerate for at least 1 hour before using.
Make Ahead: The chocolate mousse can be made up to 2 days ahead and stored in the refrigerator.
How to Make the Chocolate Ganache
The silky smooth chocolate ganache is the perfect addition to put this cake over the top and it's super simple to make.
- Warm the cream in a pot until just simmering, then pour over the chopped chocolate in a medium bowl and let sit for a few minutes.
- Stir until smooth and let it sit for 20 minutes before using to set up.
For a detailed tutorial on making chocolate ganache, check out this article on Sally's Baking Addiction.
Assembling the Cake
- To assemble the cake, begin by slicing the cakes in half lengthwise to create 4 layers of cake.
- Using an icing spatula, spread approximately 1½ cups of mousse on top of the first 3 layers of cake. Reserve around ½ cup of mousse to spread a thin crumb coat around the sides of the cake. Refrigerate for around 30 minutes to an hour to allow the cake to set up.
- Using a rubber spatula, scrape the ganache out on to the top of the cake and use an icing spatula to spread it over the top and sides of the cake.
Decorating the Cake
This chocolate mousse cake is stunning with a simple decoration of shaved chocolate to the top and sides of the cake and topped with fresh berries. You could also make chocolate curls if you prefer something fancier.
Storage Instructions
The cake can be covered and stored in the refrigerator for up to 5 days.
You can also freeze the finished cake. Allow the cake to thaw overnight in the fridge and bring to room temperature before serving.
Chocolate Mousse Cake Tips and FAQs
I use a dutch-processed cocoa powder in this recipe. It is treated with alkaline to be less bitter than natural cocoa powder and has a more intense chocolate flavor.
I also recommend using a high fat content cocoa powder. Cocoa powders are sold in two tiers; low fat, typically containing 10 to 12% cocoa butter, and high fat which is typically 20 to 22% cocoa butter. This higher fat content adds more richness to the cake.
Check out this article from Cook's Illustrated for more details on choosing a cocoa powder
If you don't like coffee and are concerned about the espresso powder, don't worry, you won't taste the coffee flavor at all. But it really enhances and deepens the chocolate flavor.
If you don't have espresso powder on hand you can use hot coffee in place of the boiling water for a similar effect.
I recommend using a high quality semi sweet baking chocolate bars in this recipe for the best results.
You can use high quality chocolate chips, such as Ghirardelli in the mousse and ganache if needed.
If you need a main course to pair with this cake for a special occasion, check out these great options:
- Steak Au Poivre
- Seared Scallops with Parmesan Risotto
- Garlic and Herb Crusted Standing Rib Roast
- Easy Creamy Chicken Marsala
📖 Recipe
Chocolate Mousse Cake
Ingredients
Dark Chocolate Cake
- 2 cups granulated sugar
- 1 ¾ cups all-purpose flour
- ¾ cup unsweetened cocoa powder
- 1 teaspoon espresso powder
- 1 ½ teaspoons baking powder
- 1 ½ teaspoons baking soda
- 1 teaspoon salt
- 2 large eggs
- 1 cup milk, or buttermilk
- ½ cup oil, vegetable or canola oil
- 2 teaspoons vanilla extract
- 1 cup boiling water
Chocolate Mousse
- ½ cup hot water
- ¼ cup unsweetened cocoa powder
- two 4-ounce semi-sweet chocolate bars, finely chopped
- 2 cups heavy whipping cream
- 2 Tablespoons powdered sugar
- ½ teaspoon vanilla extract
Chocolate Ganache
- two 4-ounce semi-sweet chocolate bars, finely chopped
- 1 cup heavy whipping cream
Instructions
Chocolate Cake
- Preheat your oven to 350°F. Prepare two 8 inch round cake pans with non-stick baking spray or grease and flour.
- Add the sugar, flour, cocoa powder, espresso powder, baking powder, baking soda and salt to a large mixing bowl and whisk to combine.
- Add the eggs, milk, oil and vanilla to the dry mixture and mix with an electric hand mixer, starting on low and gradually increasing to medium speed for 1 to 2 minutes until smooth. Set the mixer speed to low and slowly pour in the boiling water (or hot coffee). Mix on low until just combined.
- Divide the batter between the pans and bake for about 35 minutes, until a toothpick inserted into the middle comes out clean. Let the cakes cool completely in the pan.
Chocolate Mousse
- Add the cocoa powder to a medium bowl. Pour in the hot water and whisk to combine, then set aside.
- Melt the chopped chocolate bars in a double boiler or carefully in the microwave in 15-20 second increments, stirring between each one, until melted. Pour in the reserved cocoa mixture and stir to combine, then set aside.
- In a stand mixer fitted with a whisk attachment add the heavy whipping cream, powdered sugar, and vanilla and mix on medium-high speed until peaks form.
- Using a rubber spatula, scrape the chocolate mixture into the whipped cream and gently fold to combine. Cover and refrigerate for at least 1 hour before using.
Chocolate Ganache
- Warm the cream in a pot until just simmering. Pour over the chopped chocolate in a medium bowl and let sit for a few minutes to soften the chocolate.
- Stir until smooth and let it sit for 20 minutes before using.
Assembling the Cake
- Slice the cakes in half lengthwise to create 4 layers of cake.
- Using an icing spatula, spread approximately 1½ cups of mousse on top of the first 3 layers of cake. Reserve around ½ cup of mousse to spread a thin crumb coat around the sides of the cake. Refrigerate for around 30 minutes to an hour to allow the cake to set up.
- Using a rubber spatula, scrape the ganache out on to the top of the cake and use an icing spatula to spread it over the top and sides of the cake.
- The cake can be covered and stored in the refrigerator for up to 5 days.
Nutrition
* All nutrition information we provide are estimates based on third party calculators. We encourage you to calculate these on your own for accurate results.
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