Chocolate lovers, this Triple Chocolate Mousse Cake is made for you. A moist, dense, tender chocolate sheet cake is layered with silky chocolate ganache and finished with a light, creamy chocolate mousse for a rich homemade dessert.

This triple chocolate mousse cake is the kind of dessert that delivers chocolate in every bite without feeling fussy or overly complicated. It starts with a homemade chocolate cake that is soft, moist and full of cocoa flavor. Once the cake has cooled, it is covered with a glossy layer of chocolate ganache, then topped with a fluffy chocolate mousse that makes the whole dessert feel extra special.

If you love chocolate cake, chocolate ganache and chocolate mousse, this recipe brings all three together in one generous 9×13-inch cake. It is easier than a layered celebration cake, but it still looks impressive when sliced and served. The sheet cake format also makes it great for birthdays, holidays, potlucks, family dinners or any occasion that calls for a deeply chocolatey dessert.

3 Types of Chocolate in this Triple Chocolate Cake

This homemade triple chocolate mousse cake has three main chocolate components. Each layer is simple on its own, but together they create a rich, creamy and satisfying dessert.

1. Chocolate Cake: The base is a thick, moist and fudgy chocolate cake baked in a 9×13-inch pan. It has a soft crumb, deep cocoa flavor and enough structure to hold the ganache and mousse topping.
2. Chocolate Ganache: A simple two-ingredient ganache made with chocolate and heavy cream adds a smooth, rich layer between the cake and mousse.
3. Chocolate Mousse: This mousse is a simplified version made by folding whipped cream into cooled chocolate ganache. There are no eggs, gelatin or complicated stovetop steps.

The Best Chocolate Cake

A homemade chocolate cake gives this dessert its best flavor and texture. Boxed cake mix may be convenient, but this from-scratch version creates a richer, softer and more memorable result. The cake is made with butter, sugar, eggs, sour cream, cocoa powder and buttermilk, which work together to create a moist and tender crumb.

Because this is a butter-based cake, beating the butter and sugar together properly is important. Creaming them until pale and fluffy helps create a softer texture. The sour cream adds moisture and tenderness, while the buttermilk helps keep the cake light enough to balance the ganache and mousse.

Vanilla and instant espresso powder are also used to enhance the chocolate flavor. The espresso powder does not make the cake taste like coffee; it simply deepens the cocoa flavor and makes the chocolate taste more intense. For an even more chocolate-packed cake, chocolate chips can be added to the batter if desired.

One of the best parts of this recipe is that it is baked as a sheet cake. There is no need to stack, fill or frost multiple layers. Simply spread the batter into a greased 9×13-inch pan and bake until the cake springs back lightly and a toothpick inserted into the center comes out clean.

Chocolate Ganache

The ganache layer is simple, rich and smooth. It is made by combining chocolate chips with heavy cream and warming them until the mixture becomes glossy and silky. The ganache is poured over the cooled cake and spread into an even layer before the cake is chilled.

This layer adds a truffle-like texture once it sets. It also creates a delicious barrier between the cake and the mousse, giving each slice a beautiful combination of moist cake, smooth ganache and creamy topping. Let the ganache chill completely before adding the mousse so the layers stay neat and defined.

How to Make Chocolate Mousse

Traditional chocolate mousse can involve eggs, egg whites, cooking and careful temperature control. This easy chocolate mousse keeps the process much simpler while still giving you a light, creamy and chocolate-rich topping.

1. Start with the ganache: Combine chopped chocolate with hot heavy cream and stir until smooth.
2. Let the ganache cool: The chocolate mixture must cool completely before the whipped cream is added. If it is too warm, the whipped cream can melt.
3. Whip the cream: Beat cold heavy cream with powdered sugar until stiff peaks form. Wait until the ganache has cooled before doing this step.
4. Fold everything together: Gently fold the whipped cream into the cooled ganache in additions until the mousse is fully combined. Chill until firm enough to spread over the cake.

To finish the cake, spread the chilled chocolate mousse over the set ganache layer. For a simple garnish, chill a chocolate bar and use a vegetable peeler to shave curls or flakes over the top. The extra chocolate adds texture, flavor and a bakery-style finish.

Every part of this cake brings something special. The chocolate cake is moist and fudgy, the ganache is rich and smooth, and the mousse is light, creamy and deeply chocolatey. Together, they create a dessert that feels indulgent without being difficult to prepare.

Slice the cake once it is fully chilled for the cleanest pieces. Serve it cold or let it sit briefly at room temperature before serving if you prefer a slightly softer texture.

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Triple Chocolate Mousse Cake

Yield:
12 servings

Prep Time:
1 hour 40 minutes

Cook Time:
45 minutes

Additional Time:
2 hours

Total Time:
4 hours 25 minutes

This Triple Chocolate Mousse Cake features a moist homemade chocolate cake, a rich chocolate ganache layer and a fluffy chocolate mousse topping. It is a decadent sheet cake made for serious chocolate lovers.

Ingredients

Chocolate Mousse:

• 6 oz. dark or semisweet chocolate, chopped
• 1 and ½ cups (360ml) heavy cream, divided
• ¼ cup (40g) powdered sugar

Chocolate Cake:

• 2 and ¼ cups (288g) all-purpose flour
• 1 and ½ cups (150g) unsweetened cocoa powder
• 1 and ½ teaspoons salt
• 2 and ¼ teaspoons baking soda
• 1 teaspoon baking powder
• 1 and ½ cups (340g) unsalted butter, room temperature
• 2 and ¼ cups (452g) granulated sugar
• 4 large eggs, room temperature
• ¾ cup (180g) sour cream, room temperature
• 1 and ½ tablespoons pure vanilla extract
• 1 and ½ tablespoons instant espresso powder
• 2 and ¼ cups (540ml) buttermilk, room temperature

Chocolate Ganache:

• 1 cup (175g) dark chocolate chips
• ½ cup (120ml) heavy cream

Topping:

• 1 dark chocolate bar

Instructions

For the Chocolate Mousse:

1. Place the chopped chocolate in a large bowl and set aside.
2. Heat ½ cup of heavy cream in a small saucepan, stirring constantly, until it just begins to simmer.
3. Remove the hot cream from the heat, pour it over the chocolate and stir slowly until smooth. Cover the bowl and refrigerate, stirring occasionally, for about 30 minutes or until cooled.
4. Whip 1 cup of heavy cream with the powdered sugar in a stand mixer fitted with a whisk attachment, or in a large stainless steel mixing bowl using a hand mixer, until stiff peaks form, about 4-5 minutes.
5. Stir the cooled ganache to loosen it. Using a rubber spatula, gently fold the whipped cream into the ganache, about ⅓ at a time, until fully incorporated.
6. Cover the bowl with plastic wrap, placing the wrap directly on the surface of the mousse. Refrigerate for 1-2 hours or overnight.

For the Chocolate Cake:

1. Preheat the oven to 350°F (177°C). Grease a 9×13-inch pan and set aside.
2. In a large bowl, sift the flour, cocoa powder, salt, baking soda and baking powder. Whisk to combine and set aside.
3. In the bowl of a stand mixer fitted with a paddle attachment, beat the butter and sugar on medium speed until pale and fluffy, about 4-5 minutes. Scrape down the sides and bottom of the bowl.
4. Reduce the speed to medium-low and add the eggs one at a time, mixing after each addition until just combined. Scrape down the bowl as needed.
5. In a small bowl, combine the vanilla extract and instant espresso powder. Add the sour cream and vanilla espresso mixture to the batter and beat on medium speed until combined.
6. Alternate adding the dry ingredients in thirds and the buttermilk in two additions, beginning and ending with the dry ingredients. Mix each addition just until combined.
7. Pour the batter into the prepared pan and spread it evenly.
8. Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean and the cake springs back when lightly touched.
9. Remove the cake from the oven and allow it to cool completely.

For the Ganache:

1. Place the chocolate chips and heavy cream in a heat-safe bowl. Microwave in 30-second intervals for about 1 minute total, stirring until the mixture becomes smooth and silky.
2. Pour the ganache over the cooled cake and spread it into an even layer. Loosely cover the cake and refrigerate until the ganache is set, about 1 hour.

Assembly:

1. Spread the chilled chocolate mousse evenly over the set ganache layer.
2. Use a vegetable peeler to shave the chocolate bar over the top.
3. Slice, serve and enjoy.

Nutrition Information:

Yield: 12
Serving Size: 1

Amount Per Serving:
Calories: 214
Total Fat: 13g
Saturated Fat: 7g
Trans Fat: 0g
Unsaturated Fat: 5g
Cholesterol: 69mg
Sodium: 224mg
Carbohydrates: 22g
Fiber: 2g
Sugar: 17g
Protein: 4g

BON APPÉTIT!