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Decadent Chocolate Mousse Cake Recipe

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The ultimate chocolate lover’s dream, our Chocolate Mousse Cake recipe features layers of moist, fluffy chocolate cake enveloping a smooth and creamy chocolate mousse filling, and finished with a luscious chocolate buttercream frosting, this dessert is perfect for any special occasion or simply to satisfy your sweet cravings. 

A chocolate layered cake filled with chocolate mousse and frosted with chocolate buttercream. Hostess At Heart
Triple Chocolate Mousse Cake with Chocolate Buttercream Recipe

Follow our step-by-step guide to create this show-stopping cake that promises to impress both in taste and presentation.

Chocolate Layered Mousse Cake

When it comes to chocolate we don’t mess around! Like our Chocolate Pudding Trifle, Chocolate Cheesecake Pie, or French Silk Pie, our Chocolate Mousse Cake is perfect for chocolate enthusiasts seeking an indulgent dessert.

Ingredients For Your Chocolate Mousse Layer Cake

All ingredients are listed on the recipe, but I wanted to share some important notes here.

Ingredients: Cocoa, flour, sugar, butter, vanilla, buttermilk, salt, chocolate chips, baking powder, baking soda, cream, and eggs used to make a chocolate mousse cake with chocolate fudge filling and chocolate buttercream frosting - Hostess At Heart
Chocolate Mousse Cake Ingredients

Layered Chocolate Cake from scratch

We use All-Purpose Flour. You can use bleached or unbleached flour. One doesn’t act or taste any differently from the other. Unbleached flour is less processed since it doesn’t go through the bleaching step.

Be sure to use Unsweetened Cocoa Powder. The darker the cocoa powder, the darker the results. We love dark cocoa powder’s rich flavor and aesthetics but you can use what you prefer. We used cocoa powder in the cake, mousse filling, and the chocolate buttercream frosting.

Baking soda (and/or baking powder) is Called a leavening agent that gives baked goods the right texture and rise. They should be replaced every 6 months or tested for potency. We show you how in our Basic Baking Techniques article.

We use full-fat butter, buttermilk, and cream in this recipe. It adds richness to the recipe and the additional fat makes baked goods soft and tender. If you don’t have any, buttermilk you can make your own using our instructions.

Using fresh grade A large eggs creates structure and stability within the batter and adds moisture to our cake.

When it comes to chocolate mousse, the type of chocolate chips you use can make all the difference! I’d recommend using semi-sweet chocolate chips for the perfect balance of richness and sweetness. They have enough cocoa flavor to make the mousse decadent but aren’t so bitter that they overwhelm the dessert. Use good quality chocolate chips. The better the chocolate the better the results.

How To Make Chocolate Mousse Cake Recipe

Heat oven to 350 °F and grease and flour two round 8” baking pans. Pull your ingredients out and double-check that you have everything on the list.

Make the Chocolate Mousse Cake Filling

We start with the chocolate mousse filling so it can chill while we bake our cake.

Stir the cocoa powder and hot water together. In a microwave, melt the chocolate chips and stir until melted and smooth. Add the cocoa mixture and stir. Cool.

In a separate mixing bowl beat the cream and sugar until very stiff peaks form. Add the chocolate mixture and gently fold it all together. Refrigerate.

A bowl filled with thick chocolate mousse filing.

Make and bake the cake

Stir together the dry ingredients; sugar, flour, cocoa powder, baking powder, baking soda, and salt in a large bowl.

In a large bowl combine the wet ingredients; eggs, buttermilk, oil, and vanilla. Spoon in the dry ingredients. Stir in boiling water (it will be a thin batter). Pour batter into prepared pans.

Note: You can use an electric mixer to make this cake.

Bake for about 30 to 35 minutes or until a toothpick inserted in the center comes out clean. Allow the cake to cool in the pan for 5 minutes and then remove them from the pans and place them on a wire rack to cool completely.

Chocolate Buttercream Frosting

In a medium saucepan, add milk, cocoa, and butter. Bring to a boil over medium-high heat. When smooth, remove from heat. Add powdered sugar and whisk until smooth. This step can be done with an electric mixer. Cool completely.

Assemble

Once the cakes have cooled, cut each cake evenly in half horizontally. Stack and spread each layer with the chocolate mousse. Refrigerate for 30 minutes. Frost the chilled cake by spreading the frosting gently so as not to disturb the chocolate mousse. Refrigerate.

Popular Variations & Additions

  • For this recipe, I use a “boiled” chocolate buttercream frosting. You can use a no-cook buttercream recipe as well.
  • Add chopped walnuts, pecans, or shredded toasted coconut to the top of this cake.
  • Use hot coffee instead of hot water when making the mousse. It will add an intensity to the chocolate flavor.

FAQ’s

Is mousse the same as pudding?

No, they’re not the same. Unlike pudding, mousse isn’t cooked. Mousse is made by folding whipped cream in this recipe.

Best Way To Store

Refrigerate this cake. Don’t leave it at room temperature for more than 2 hours. Refrigerate for up to 4 days, covered in an airtight container. The mousse will eventually get weepy.

Can I Freeze Chocolate Cake With Mousse Filling

No, I don’t recommend freezing this chocolate mousse cake. The mousse layer is full of air, making it light and fluffy. After you freeze it, the cake will not have a light and fluffy consistency and will dry out.

Can Chocolate Cake With Mousse Filling be made ahead of time?

You can bake the cake, make the buttercream frosting, and make the chocolate mousse up to 2 days in advance. Store them separately in airtight containers. Allow the cake to cool completely and then wrap the layers in plastic wrap before refrigerating them.

If you’re making a 4-layer cake, don’t slice the layers until you’re ready to assemble the cake. Chilling the cake actually makes it easier to slice.

Front view of a slice of chocolate mousse cake showing a soft cake interior with layers of creamy mousse covered with a chocolate buttercream frosting - Hostess At Heart
Two-layer cake

Hostess Tips

Cold is your friend when making this recipe. We chill the mousse while baking the cake and chill the cake before frosting it.

Do not overwhip the mousse. Overwhipping will separate the cream into butter, causing it to become grainy.

Freezing a cake for 15 minutes makes it easier to frost.

A side view of a slice of mouse cake showing the layers of cake, mouse and frosting on a plate.
Four-layer Cake

We’ve made this cake into a two-layer and four-layer cakes. You can slice each layer for a four-layer cake. The mousse recipe is adequate for both.

This chocolate mousse cake recipe can be baked in two 8-inch pans. The cake layers will be thicker. Or, in 9-inch pans. The layers will not be as thick but will be a little wider.

You can use a double boiler to melt the chocolate chips but I find that the microwave works best at 50% power and short 15 to 20-second increments. Stir between each increment.

When assembling the chocolate mousse cake layers, put one rounded layer on top and gently slice the rounded top off of the second layer. Place it upside down on the serving plate. Not slicing the top level can cause your cake to lean. You can use a serrated knife or a cake leveler for this step.

Adding a thin layer of buttercream as a skim coat will help keep cake crumbs out of your final frosting. Let it set before adding more frosting.

Angled view of a chocolate layer cake with a slice pulled away showing a mousse filling - Hostess At Heart

I hope you enjoyed this delicious recipe as much as we do. Drop me a comment below, and don’t forget to give it a star rating. ⭐⭐⭐⭐⭐. Your comments and ratings help others decide if this recipe is for them too.

A slice of cake with a chocolate mousse filling being lifted from a round chocolate layer cake. Hostess At Heart

Chocolate Mousse Cake

Author: Julie Menghini
Chocolate Mousse Cake combines layers of moist and fluffy chocolate cake spread with smooth and creamy chocolate mousse. Then the cake is covered in a perfect chocolate buttercream frosting for the ultimate intensity of chocolate in every bite.
4.80 from 5 votes
Prep Time 45 minutes
Cook Time 35 minutes
Total Time 1 hour 20 minutes
Course Dessert
Cuisine American
Keyword: Chocolate Buttercream Frosting, Chocolate Cake
Servings: 12 servings

Ingredients
 
 

Chocolate Cake Ingredients

  • 2 cups granulated sugar
  • 1 ¾ cups flour plus 2 tbsp
  • ¾ cup cocoa powder
  • 1 ½ tsp baking powder
  • 1 ½ tsp baking soda
  • 1 tsp salt
  • 2 eggs
  • 1 cup buttermilk
  • ½ cup canola oil
  • 2 tsp vanilla extract
  • 1 cup boiling water or hot coffee

Chocolate Mousse Ingredients

  • ½ cup hot water
  • 4 tbsp cocoa powder
  • 1 ½ cups semi-sweet chocolate chips
  • 2 cups heavy cream
  • 2 tbsp sugar

Chocolate Buttercream Frosting

  • 6 tbsp milk
  • 3 tbsp cocoa powder
  • ½ cup butter softened
  • 3 ¾ cup powdered sugar

Instructions
 

  • Preheat oven to 350 °F and grease and flour two round 8” or 9” baking pans.

Chocolate Mousse Cake Filling

  • Stir the cocoa powder and hot water together.
  • In a microwave, melt the chocolate chips just until smooth. Add the cocoa mixture to the melted chocolate chips and stir well to combine. Allow to cool to room temperature.
  • In a separate large bowl, beat the cream and sugar until very stiff peaks form. Add the chocolate mixture and fold in with a spatula until well combined. Refrigerate until ready to use.

Chocolate Cake Instructions

  • Stir together sugar, flour, cocoa powder, baking powder, baking soda and salt in large bowl.
  • Add eggs, buttermilk, oil, and vanilla then mix until combined. Turn the mixer on low and spoon in the dry ingredients. Once incorporated, mix on medium speed for 2 minutes.
  • Stir in boiling water (it will be a thin batter). Pour batter into prepared pans.
  • Bake for about 30 to 35 minutes or until a toothpick inserted in the center comes out clean.
  • Allow cake to cool in the pan for 5 minutes and then remove to wire cooling racks. Cool completely.

Chocolate Buttercream Frosting Instructions

  • In a medium saucepan, add milk, cocoa, and butter. Bring to a boil. Remove from heat.
  • Add powdered sugar and mix with electric beaters to get rid of any lumps. Allow to cool for 15-20 minutes, stirring occasionally.

Chocolate Mousse Cake Assembly Instructions

  • Once cakes have cooled, use a sharp serrated knife to level each layer cake evenly. If making a 4-layer cake, slice each layer horizontally, so that you end up with four, thin, 8” or 9” cake pieces.
  • Place your first cake layer on your cake serving plate or pedestal. Spread a big spoonful of mousse on top of that cake layer. Repeat with the remaining cake layers, adding a layer of mousse filling between each layer of cake.
  • Use remaining mousse filling to spread it evenly around the entire outside and top of the cake. Refrigerate for 30 minutes.
  • Remove cake from fridge and very slowly pour the cooled chocolate frosting over the top. Use a spatula or knife to gently spread the frosting evenly over the outside of the cake as you pour.

Notes

After filling the cake with the mousse layer it should be refrigerated for 20 to 30 minutes. At that time I chose to put the cake in the freezer for 15 minutes making it easy to frost.
Store this cake in the refrigerator for up to 4 days. We don’t recommend freezing it.

Nutrition

Calories: 812kcalCarbohydrates: 106gProtein: 8gFat: 43gSaturated Fat: 21gPolyunsaturated Fat: 4gMonounsaturated Fat: 15gTrans Fat: 0.4gCholesterol: 97mgSodium: 443mgPotassium: 414mgFiber: 5gSugar: 83gVitamin A: 915IUVitamin C: 0.2mgCalcium: 115mgIron: 4mg

Nutritional Disclaimer

This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.

Tried this recipe?Let me know how it was!

If you’re looking for more chocolate cake recipes, we’ve got you covered. Check out our old-fashioned Mahogany Cake, Chocolate Syrup Cake, and Raspberry Chocolate Bundt Cake. They’re amazing!

Did you enjoy this recipe? Don’t forget to pin it for later and follow me on Pinterest for more delicious recipes like this one!

An image for pinterest of a Chocolate Mousse Cake slice being lifted from the whole cake showing the dark chocolate cake filled with creamy chocolate mousse. Hostess At Heart
The BEST Chocolate Mousse Cake Recipe

Our Chocolate Mousse Cake recipe has been updated to improve our readers’ experience. We added simple details and new images. No changes were made to the actual recipe.

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4.80 from 5 votes (3 ratings without comment)

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10 Comments

  1. I can’t believe how easy this delectable chocolate mousse cake was to make. The flavors are incredible, and my whole family loved it!

  2. Julie this delicious cake is epic and love your helpful step by step instructions. We don’t make desserts often but when we do we go big. We are going to add the coffee for a little kick.