Name: Chocolate Mousse Crunch Cake Recipe
Prep time: 20 min
Cook time: 35 min
Total time: 1 h 25 min
Cuisine: American
Ingredients: 1 package Duncan Hines Devil’s Food Cake mix; 1 teaspoon unflavored gelatin; 1 tablespoon cold water; 2 tablespoons boiling water; 1/2 cup sugar; 1/4 cup unsweetened cocoa powder; 1 cup whipping cream; 1 teaspoon vanilla extract; 1 recipe Chocolate Ganache (prepare separately); Crushed Heath bars or chocolate-covered Heath bits, as needed; Optional: extra sweetened whipped cream for serving

Jump to Recipe· 4.1 from 53 reviews

If you have a serious sweet tooth and a love for everything chocolate, then this Chocolate Mousse Crunch Cake Recipe is going to become your new best friend in the kitchen. Imagine two layers of rich, moist chocolate cake nestled around a luxuriously smooth chocolate mousse filling, all crowned with a glossy drizzle of silky ganache and topped with crunchy toffee bits that add the perfect satisfying contrast. Whether it’s a birthday, anniversary, or just because, this cake delivers a spectacular showstopper that tastes even better than it looks. Trust me, once you try this Chocolate Mousse Crunch Cake Recipe, your dessert game will level up forever.

Ingredients You’ll Need

The image shows a round two-layered dessert on a white plate with wavy edges. The bottom layer is a dark brown dense chocolate cake with a moist texture. The top layer is a thick, light brown chocolate cream spread evenly with smooth swirls. On top of the cream layer, there are small, uneven pieces of chopped nuts scattered, giving a crunchy texture. The dessert is placed on a white marbled surface with some crumbs around it. photo taken with an iphone --ar 4:5 --v 7

You don’t need a pantry full of fancy ingredients to make this cake shine—just a handful of carefully chosen staples that work together beautifully to create layers of flavor and texture. Each component brings its own magic, from the deep cocoa richness to the creamy lightness of the mousse, and the irresistible crunch of toffee bits on top.

1 package Duncan Hines Devil’s Food Cake mix: This creates the perfect moist and chocolatey cake base that supports all the decadent layers.
1 recipe Chocolate Ganache: Smooth, glossy, and chocolatey, ganache adds a luscious finishing touch that ties everything together.
Crushed Heath bars or chocolate-covered Heath bits: The crunch factor—the sweet toffee bits add an amazing contrast to the creamy mousse and soft cake.
1 teaspoon unflavored gelatin: Helps set the mousse for that perfect, cuttable texture without heaviness.
1 tablespoon cold water: Works to bloom the gelatin, essential for the mousse’s silky structure.
2 tablespoons boiling water: Activates the gelatin, giving the mousse its stability.
1/2 cup sugar: Balances the cocoa’s natural bitterness and sweetens the mousse wonderfully.
1/4 cup unsweetened cocoa powder: Packs an intense chocolate punch into the mousse.
1 cup whipping cream: Whipped to medium-stiff peaks, this brings airy richness perfect for mousse.
1 teaspoon vanilla extract: Enhances the chocolate flavor with subtle warmth and complexity.
Optional: extra sweetened whipped cream for serving: If you want to make your presentation extra indulgent and creamy on top.

How to Make Chocolate Mousse Crunch Cake Recipe

Step 1: Bake the Cake Layers

Start by preparing the Devil’s Food Cake mix according to package instructions, baking it in two 8-inch round pans. This is the foundation of your dessert, so be sure to bake until just right—moist but fully set. Once baked, allow the cakes to cool completely. Fun tip: You can even bake these a few days ahead and freeze them to save time when you’re ready to assemble.

Step 2: Prepare the Gelatin Mixture

Place the gelatin in a small bowl with the cold water and let it bloom for about a minute. Then stir in the hot boiling water until it dissolves completely. Allow this mixture to cool slightly so it doesn’t melt the cream when folded into the mousse later.

Step 3: Whip the Chocolate Mousse

In a medium bowl, combine the sugar, unsweetened cocoa powder, whipping cream, and vanilla. Beat with an electric mixer until the cream reaches medium-stiff peaks—light, fluffy, but still stable. Gently fold in the gelatin mixture for that perfect mousse consistency, then refrigerate for at least 30 minutes to set slightly and develop that melt-in-your-mouth texture.

Step 4: Level and Assemble the Cake

Using a serrated knife, carefully slice off the domed tops of the cakes to create even layers. Place one cake layer on your serving plate, generously spread a layer of the chilled chocolate mousse over it, and then sprinkle crushed Heath bits on top for that delightful crunch. Place the second cake layer over this, pressing down lightly for stability.

Step 5: Finish with Ganache and Toppings

Pour chocolate ganache over the top of the cake, letting it drip seductively down the sides. Before refrigerating, sprinkle more Heath bits on top to lock in that signature crunch. If you love a bit more decadence, a cloud of sweetened whipped cream on top is always a dream.

How to Serve Chocolate Mousse Crunch Cake Recipe

A two-layer dark chocolate cake sits on a white plate with a wavy edge, with a smooth light brown chocolate frosting layer between the cake layers. The top layer is covered with shiny chocolate ganache that drips down the sides, topped by a thick, fluffy white whipped cream layer sprinkled with small, chopped light brown and dark bits. Some crumbs and pieces are scattered on the plate around the cake. The background is a white marbled texture photo taken with an iphone --ar 4:5 --v 7

Garnishes

Simple garnishes can elevate your dessert presentation in an instant. Consider a light dusting of cocoa powder, elegant curls of dark or white chocolate, or even a few fresh berries to cut through all that richness. Crispy toffee bits sprinkled on top add irresistible texture and eye appeal.

Side Dishes

Pair this decadent cake with a scoop of vanilla bean ice cream or a dollop of freshly whipped cream to balance the intense chocolate flavors. Fresh fruit, especially raspberries or strawberries, works beautifully to add a little tart brightness alongside the sweet and creamy layers.

Creative Ways to Present

For a special occasion, try serving this cake on a sleek slate board or a rustic wooden platter for contrast. Slice into neat wedges and plate with drizzle of raspberry coulis or a dusting of powdered sugar. For an interactive twist, offer extra crushed toffee bits or ganache on the side for guests to customize each slice.

Make Ahead and Storage

Storing Leftovers

This cake keeps beautifully in the refrigerator, where the mousse stays firm and the cake moist. Store leftovers in an airtight container or cover tightly with plastic wrap to prevent the cake from absorbing fridge odors. It’s best enjoyed within 3 to 4 days for peak freshness.

Freezing

You can freeze the cake layers in advance, tightly wrapped in plastic and foil. Once thawed completely in the fridge, assemble and decorate as directed. If you have leftovers after assembling the full cake, freezing isn’t ideal because mousse textures can change, but it can work in a pinch—just thaw slowly in the fridge to preserve texture as much as possible.

Reheating

This cake is best enjoyed chilled. If you prefer softer mousse, simply leave slices out for 10 to 15 minutes before serving to take the chill off. Avoid microwaving as it will alter the delicate mousse and ganache texture.

FAQs

Can I make the mousse without gelatin?

Gelatin is key to giving the mousse its stable, slice-worthy texture in this recipe. If you don’t want to use gelatin, consider whipping extra cream or using a different mousse recipe, though it may be softer and less structured.

What kind of chocolate works best for the ganache?

Use a good quality bittersweet or semisweet chocolate for ganache to balance sweetness and richness. Avoid milk chocolate—it can be too sweet and doesn’t set as firmly.

How do I crush Heath bars without making a mess?

Place Heath bars in a sealed plastic bag and gently tap with a rolling pin or use the bottom of a heavy pan to crush into bits. This keeps crumbs contained and ensures even-sized chunks.

Can I use homemade chocolate cake instead of boxed mix?

Absolutely! A homemade devil’s food or chocolate cake from your favorite recipe will be delicious here. Just be sure it’s moist and sturdy enough to support the mousse layer.

How long does it take to assemble the cake?

Once the cake layers are cooled and the mousse is chilled to the right consistency, assembly is quick—about 15 to 20 minutes. The chilling time for the mousse is the main thing to plan around beforehand.

Final Thoughts

Honestly, this Chocolate Mousse Crunch Cake Recipe is one of those desserts that’s guaranteed to impress guests and satisfy serious chocolate cravings alike. Its balance of textures, flavors, and stunning presentation make it a recipe you’ll want to keep coming back to for birthdays, holidays, or any day that calls for something truly special. So grab your apron, whip up this show-stopping cake, and enjoy every chocolatey, crunchy, creamy bite with the people you love!