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If you’re looking for a show-stopping dessert, this Triple Layer Chocolate Mousse Cake is it! With a moist chocolate cake base, a fluffy chocolate mousse layer, and rich ganache on top, it’s everything you love in one decadent bite. Whether you go easy with a 9×13 version or stack it high as a layer cake, I’ve got all the tips and options waiting for you below!
This Triple Layer Chocolate Mousse Cake is ALWAYS a good idea!
My family and friends know that when I bake a cake, it’s going to be something special. Two of their all-time favorites are my Chocolate Oreo Cake and my Chocolate Brownie Cake—both deliciously easy thanks to cake mixes. But I’ve been wanting to create a truly from-scratch chocolate cake that’s just as irresistible—one with rich layers, homemade flavor, and a touch of wow.
This cake has it all: a super moist chocolate base, a light and fluffy layer of whipped chocolate mousse, and a silky ganache that ties it all together. It’s basically a chocolate lover’s dream—a trifecta of deliciousness. I first made it for a sweet friend’s birthday from my Bible study group, and the rave reviews told me everything I needed to know… this one’s a keeper, and I couldn’t wait to share it with you!
What You’ll Need for this Triple Chocolate Mousse Cake
This insanely rich and decadent cake can be made in two ways: a simple sheet cake version or a beautifully decorated layer cake. Either way, there are 3 components to the chocolate mousse cake.
Chocolate Cake
- All-Purpose Flour
- Granulated Sugar
- Unsweetened Dark Cocoa Powder
- Unsweetened Cocoa Powder
- Baking Soda
- Baking Powder
- Salt
- Vegetable or Canola Oil
- Eggs: room temperature
- Sour Cream: room temperature
- Buttermilk: room temperature
- Vanilla Extract
- Hot Coffee or Hot Water
Chocolate Mousse
- Hot Water
- Cocoa Powder: natural, unsweetened
- Semi-Sweet Chocolate: – 2 – 4 ounce premium quality semi-sweet chocolate bars. They can be found in the baking aisle at your grocery store.
- Heavy Cream
- Powdered (or Confectioners) Sugar
- Vanilla Extract
TIP: Chocolate mousse needs to be well chilled. Make sure to allow time to put in the refrigerator before putting on the cake. You can make this up to 2 days ahead of time or make it while the cake is baking and cooling. Mousse tastes so much better cold. This cake will assemble and serve much more easily when chilled.
Also, if you prefer to use milk chocolate, that is perfectly fine. Use the flavors you love. Just remember to get good-quality chocolate.
Ganache
Chocolate ganache is so simple to make. It is super decadent and delicious, but it is only as good as the chocolate you use.
- Semi-Sweet Chocolate Bars: Make sure you are using premium-quality baking bars.
- Heavy Cream
Also, make sure to allow time for the ganache to cool for 20 minutes before pouring it over the cake.
If making a sheet cake and you want the ganache in the center layer, pour it over the cooled cake and then refrigerate for an hour to set up. Then add the chocolate mousse for your top layer. Top with curled chocolate shavings for a stunning presentation.
How to Make Triple Chocolate Mousse Cake: 2 Methods
This cake can be made into a simple yet beautifully decadent sheet cake or an elegant round layer cake. Both instructions and cook times are included in the recipe card below. Either cake will WOW your guests with the same chocolate flavor!
Step 1: Prep Your Pans
Preheat the oven to 350°F.
Grease or spray a 9×13 pan with baking spray, or grease two or four 8- or 9-inch round cake pans. Line round pans with parchment paper and grease the parchment—this makes releasing the cakes a breeze. If you’re planning to lift the 9×13 cake out of the pan, I recommend lining that with parchment too. Set aside.
Step 2: Make the Chocolate Cake
Dry Ingredients:
In a large mixing bowl, whisk together the flour, both cocoa powders, sugar, baking soda, baking powder, and salt until everything is well combined.
Wet Ingredients:
In a separate large bowl or the bowl of a stand mixer, beat together the oil, sour cream, eggs, and vanilla extract at medium to high speed until it is smooth. Add the buttermilk and mix again until thoroughly combined.
Combine Wet and Dry Ingredients:
Gradually add the dry ingredients into the wet, mixing just until the batter comes together.
Then pour in the hot coffee (or hot water) and beat until your batter is smooth. It’ll be a little thinner than you might expect—that’s what makes it so moist and tender!
Step 3: Bake the Cake
Pour the batter into your prepared 9×13 pan or divide evenly between your round pans.
- For a 9×13 cake, bake for 30–40 minutes.
- For four round layers, bake for 19–23 minutes.
- For two round layers, bake for 23–26 minutes, then slice in half for four thin layers.
Cakes are done when a toothpick inserted in the center comes out clean. Let cakes cool completely in the pans on a wire rack.
Step 4: Make the Whipped Chocolate Mousse
(Plan ahead—this needs at least 2 hours to chill.)
Start by whisking together hot water and cocoa powder until smooth and blended.
Melt your chopped chocolate bars using a double boiler or microwave in short bursts, stirring until completely melted and silky. Stir the melted chocolate into the cocoa mixture with a spatula until smooth.
In a stand mixer or with a hand mixer, whip the heavy cream, powdered sugar, and vanilla together at medium-high speed until medium peaks form. This takes about 3 to 4 minutes.
Gently fold the chocolate mixture into the whipped cream using a spatula.
Take your time and be gentle to keep that mousse nice and fluffy. Cover and refrigerate for at least 2 hours, or up to 2 days, until fully chilled.
Step 5: Prepare the Ganache
While the cake cools, make the ganache:
Place semi-sweet chocolate in a medium heatproof bowl.
In a small saucepan, heat heavy cream over medium until gently simmering (don’t boil).
Pour cream over the chocolate and let sit for 2–3 minutes.
Stir until smooth and glossy.
Let the ganache cool at room temperature for 20 minutes before using.
Assembling the Cake
Option 1: Easy 9×13 Sheet Cake
You’ve got two options here:
- Ganache First: Pour ganache over the cooled cake and refrigerate for 1 hour. Then spread the chilled mousse on top.
- Mousse First: Spread the mousse over the cooled cake, then drizzle ganache over the top like a glaze.
Both are delicious and picture-perfect in their own way!
Option 2: Layered Round Cake
Level cake layers if needed by trimming off domed tops for flat surfaces.
For 4 layers, divide the mousse into three equal portions (about 1½ cups each).
Spread one portion of mousse between each layer, stacking as you go.
Top with the final cake layer. Reserve a small spoonful of mousse to lightly crumb-coat the sides.
Smooth the sides using a spatula or bench scraper.
Chill the cake for 1–4 hours before adding ganache.
Ganache Layer:
Pour or spoon the ganache over the chilled cake.
Then, smooth it with a spatula or scraper.
Garnish Ideas
Add a pretty finish with:
- Chocolate curls or shavings
- Chocolate chips or sprinkles
- Fresh raspberries, strawberries, or edible flowers
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Can You Make 3 Layer Chocolate Mousse Cake Ahead of Time?
This cake stores beautifully for up to 5 days, making it perfect for prepping ahead. You can bake the layers, whip up the mousse, and even assemble the cake a day or two in advance—just keep it covered and chilled. That way, when it’s time to serve, all you have to do is slice and enjoy!
Chocolate Mousse Cake Recipe Tips
- Don’t rush the chill time: The mousse needs at least 2 hours in the fridge to set up properly. You can even make it a day or two ahead—just keep it covered and cold.
- Level your cake layers: A flat surface makes for a prettier, more stable cake. Use a serrated knife or cake leveler if the tops are domed.
- Use quality chocolate: For the mousse and ganache to set up properly, the type of chocolate you use really matters. I recommend using pure chocolate baking bars—you’ll usually find them near the chocolate chips in the baking aisle, and they come in 4-ounce bars. I personally like Bakers or Ghirardelli. You can use high-quality chocolate chips in a pinch (Ghirardelli semi-sweet chips are my go-to), but baking bars will give you the best texture and melt.
- Keep it cool: Once assembled, refrigerate the cake until serving to keep the mousse firm and the ganache glossy.
- Make a Simple Sheet Cake: Don’t feel like stacking layers? Bake it in a 9×13 pan for an easy, fuss-free version that’s just as delicious.
How to Store Leftover Layered Chocolate Mousse Cake
Serving & Storing Tips
- Once your cake is assembled and frosted, serve immediately or chill uncovered for 4–6 hours before slicing.
- Store any leftovers covered in the refrigerator. You can use a cake dome or an airtight container. The cake will stay moist and delicious for up to 5 days in the fridge.
Pro Tip: Pressed a couple of layers of plastic wrap against the cut sides to keep it fresh.
Freezing Tips:
Yes, you can absolutely freeze this cake! For best results, slice the cake and wrap each slice tightly in plastic wrap, then in foil.
- Place the wrapped slices in a freezer-safe container or zip-top bag and freeze for up to 1 month.
- When you’re ready to enjoy, thaw the slices in the refrigerator overnight or let them sit at room temperature for about 30 minutes.
Other Delicious Cake Recipes You Will Love!
- Chocolate Cake with Whipped Oreo Icing
- White Chocolate Macadamia Nut Pound Cake
- Coconut Cream Poke Cake
- Lemon Pudding Poke Cake
- Snickers Poke Cake
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Layered Chocolate Mousse Cake Recipe
Ingredients
Chocolate Cake
- 1 ¾ cup all-purpose flour
- 1 and 3/4 cups granulated sugar
- ¼ cup unsweetened dark cocoa powder
- ½ cups unsweetened cocoa powder
- 2 teaspoons baking soda
- 1 teaspoons baking powder
- 1 teaspoon salt
- ½ cup vegetable or canola oil
- 2 large eggs, room temperature
- ¾ cups sour cream, room temperature
- ½ cup buttermilk, room temperature
- 2 teaspoons vanilla extract
- ½ cup hot coffee or hot water
Chocolate Mousse Filling / Topping
- ½ cup hot water
- ½ cup unsweetened cocoa powder
- 8 ounces quality semi sweet chocolate bars, chopped
- 2 cups heavy cream or heavy whipping cream
- 2 Tablespoons powdered sugar, confectioners sugar
- ½ teaspoon vanilla extract
Chocolate Ganache
- 8 ounces quality semi sweet chocolate bars, finely chopped
- 1 cup heavy cream
Instructions
- Preheat the oven to 350℉. Grease or spray a 9X13 pan with baking spray or grease two or four 8-inch or 9-inch cake pans. Then line with parchment rounds, and grease the parchment paper. Parchment paper will help release the cake from the pan. If you would like to remove the 9 X 13 cake, I recommend using parchment paper as well. Set aside.
Make the Chocolate Cake
- Make the cake: (Dry Ingredients) Whisk flour, sugar, cocoa powder, baking soda, baking powder, and salt together in a large bowl.(Wet Ingredients) In a large bowl or stand mixer on medium-high speed, mix the oil, sour cream, eggs, and vanilla until combined. Then add the buttermilk and mix until combined.Add the dry ingredients to the wet ingredients and mix until combined. Add in hot coffee or water and beat until the batter is combined.
- Pour the batter into a prepared 9×13-inch baking pan, or divide it evenly between two or four 8- or 9-inch round pans. For a 9×13 pan, bake for 30 to 40 minutes, or 4 cake layers, bake for 19 to 23 minutes. You can also bake 2 round cakes for 23 to 26 minutes and cut them in half to create 4 layers.Keep an eye on your cakes—baking times can vary. You'll know they’re ready when a toothpick inserted in the center comes out clean.
- Remove cake from oven and set the pan/s on wire racks to cool completely in the pan.
Prepare Chocolate Mousse Filling / Topping: (Chill time needed: 2 hours up to 2 days ahead)
- Whisk hot water and cocoa powder together in a bowl.
- Place chopped chocolate bars in a double boiler to melt. You can also melt them in the microwave by placing them in a heat-proof bowl and melting them in 20-second increments. Stir after each increment until melted and smooth.
- Pour melted chocolate into hot cocoa water mixture and stir in with silicone spatula until combined and smooth in texture.
- In a stand mixer or with hand mixer. Beat heavy whipping cream, powdered sugar, and vanilla together on medium-high speed until medium peaks form. About 3 to 4 minutes.
- Using a silicone spatula, gently fold the chocolate mixture into the whipped cream until combined. Do not overmix or mix too hard so that the mousse does not deflate. Cover and refrigerate 2 hours or up to 2 days until chilled.
Prepare Chocolate Ganache
- As the cakes cool, prepare the Ganache (about 25 minutes ahead of adding it to the cake) Place chopped chocolate in a medium heat-proof bowl.
- Heat cream in a small saucepan over medium heat until it begins to simmer gently (do not bring to a rapid boil). Pour over the chocolate and let it stand for 2 to 3 minutes to soften the chocolate. With a spatula stir until the chocolate is completely melted and smooth.
- Let it cool at room temperature for 20 minutes before spreading on chilled cake.
Simple 9 X 13 Layer Cake
- For a 9×13 Cake: There are two ways you can layer this cake1 – Cake / Ganache / Mousse: First, you can pour the ganache over the fully cooled chocolate cake to create a distinct ganache layer, refrigerate for 1 hour, then spread the whipped mousse on top. Or, if you prefer, pour the ganache over the cake while it’s still slightly warm so it soaks in a bit, refrigerate for 1 hour, then add the mousse once it’s cooled (as pictured in the post). 2 – Cake / Mousse / Ganache: Alternatively, you can reverse the order—spread the mousse over the cake first and drizzle the ganache on top, just like with the round layer cake version. Then garnish.
To Assemble Round Cake Layers
- Chocolate Mousse Layer: Once the cake is completely cooled, layer it with chocolate mousse.*For Layer Cakes: To assemble the cake with the whipped chocolate mousse icing, start by leveling your cake layers, if needed. If the cakes are domed, use a large serrated knife or a cake leveler to carefully slice off the rounded tops and create flat, even surfaces.For a 4-layer cake, divide the mousse into three equal portions—about 1½ cups each. Spread one portion between each of the first three layers, top with the 4th cake, reserving a spoonful to lightly coat the sides for a crumb layer.Lightly coat the sides for a crumb layer by smoothing with a spatula or bench scraper, before topping with ganache.Refrigerate cake for at least 1 hour and up to 4 hours. Prepare the ganache as you wait about 25-30 minutes before adding the ganache.
- Chocolate Ganache Layer: Pour or spoon ganache on chilled cake. Smooth the ganache with a spatula or a bench scraper.
Garnish
- Garnish with chocolate curls, sprinkles, chocolate chips or raspberries or strawberries.
Serve / Store
- Cake can be served immediately or chilled uncovered for 4–6 hours before serving.
- Cover leftover cake and store in the refrigerator for up to 5 days.
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Notes
Nutrition Information
Nutritional Disclaimer
Soulfully Made is not a dietician or nutritionist, and any nutritional information shared is only an estimate. We recommend running the ingredients through an online nutritional calculator if you need to verify any information.
©️Soulfully Made
Sounds delicious. Love using three different types of chocolate for a rich chocolate taste.
Thank you, Carol! This one is decadent for sure!