Chocolate Mousse Cake

Chocolate mousse cake is a dreamy, layered dessert that combines a rich chocolate cake base with a silky-smooth mousse center and glossy ganache topping. It’s elegant enough for special occasions but surprisingly simple to make at home!

Love More Chocolate Cakes? Try My Buttermilk chocolate cake or this Chocolate Caramel Cake next.

Why You’ll Love This Recipe

light, silky mousse layered over rich, moist chocolate cake. Elegant enough for celebrations yet simple enough to make just because you deserve something special. Every forkful melts on your tongue, delivering deep chocolate flavor without ever feeling heavy.

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Ingredient List

For the Base (Chocolate Cake)

• 1 cup all-purpose flour
• 1 cup granulated sugar
• 1/3 cup cocoa powder
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/4 teaspoon salt
• 1/2 cup milk
• 1/4 cup vegetable oil
• 1 egg
• 1 teaspoon vanilla extract
• 1/2 cup hot water

For the Mousse Layer

• 1 1/2 cups heavy cream
• 200 g dark chocolate (60–70% cocoa recommended)
• 1/4 cup powdered sugar
• 1 teaspoon vanilla extract

For the Ganache Topping

• 100 g dark chocolate
• 1/2 cup heavy cream

Friendly Notes:

• Semi-sweet chocolate chips work beautifully if you don’t have dark chocolate bars on hand
• Whipping cream can substitute for heavy cream in a pinch
• Want an even richer cake base? Swap the vegetable oil for melted butter

Why These Ingredients Work

Let me tell you why each ingredient earns its place in this stunning cake!

Hot water in the cake batter might seem odd, but it’s the secret to an incredibly moist, tender crumb. It “blooms” the cocoa powder, bringing out deeper chocolate flavor.

Dark chocolate (60-70% cocoa) gives the mousse that sophisticated, not-too-sweet taste that balances perfectly with the cake and ganache. Too much sugar would make this cloying – we want elegant indulgence here.

Heavy cream does double duty: whipped into the mousse for that cloud-like texture, and heated for the ganache to create that glossy, pourable finish.

Powdered sugar in the mousse dissolves instantly (no grainy texture!) and adds just enough sweetness without weighing down the airy structure.

Baking soda AND baking powder work together to give the cake lift and the perfect tender texture that won’t compete with the delicate mousse layer.

Essential Tools and Equipment

Here’s what you’ll need to have ready:

• 9-inch springform pan (this is KEY – you need to remove the sides!)
• Parchment paper
• Large mixing bowls
• Whisk (or hand mixer)
• Rubber spatula for folding
• Small saucepan for heating cream
• Sharp knife for chopping chocolate
• Offset spatula for smoothing (or the back of a spoon works too!)

How To Make Chocolate Mousse Cake

Step 1: Preheat & Prep

Preheat your oven to 350°F (175°C). Line the bottom of your springform pan with parchment paper and lightly grease the sides with butter or cooking spray.

Step 2: Mix Dry Ingredients

In a large bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt. This distributes everything evenly so you get consistent chocolate flavor in every bite.

Step 3: Add Wet Ingredients

Add the milk, oil, egg, and vanilla extract to your dry ingredients. Stir until the mixture is smooth and well combined. Now here’s where it gets interesting: mix in that hot water.

Step 4: Bake the Cake

Pour the thin batter into your prepared springform pan. Bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean or with just a few moist crumbs.

Step 5: Cool Completely

This is important: let the cake cool completely in the pan. I mean it, completely! If you add mousse to a warm cake, it’ll melt and you’ll have a chocolatey mess instead of beautiful layers. I usually bake the cake in the morning and let it hang out until afternoon.

Step 6: Make the Mousse

Chop your 200 g of dark chocolate and melt it gently (I use the microwave in 30-second bursts, stirring between each one). Let it cool slightly so it’s not steaming hot.

In another bowl, whip the heavy cream, powdered sugar, and vanilla until you see soft peaks forming. Don’t over-whip or it’ll get grainy!

Here’s the gentle part: fold the melted chocolate into the whipped cream in three or four additions. Use a light hand and a rubber spatula, lifting and folding to keep all that beautiful airiness. The mousse should be smooth, silky, and cloud-like.

Step 7: Assemble Part One

Spread the mousse over your completely cooled cake base, using an offset spatula or the back of a spoon to smooth the top. Pop the whole thing in the refrigerator for about 2 hours to set.

Step 8: Make the Ganache

Heat the 1/2 cup of heavy cream in a small saucepan just until it begins to simmer, you’ll see tiny bubbles around the edges. Remove from heat and pour it over your chopped 100 g of chocolate.

Step 9: Assemble Part Two

Pour the ganache over your chilled mousse layer. Tilt the pan gently to spread it evenly across the surface. The ganache will settle into a beautiful, mirror-like finish all on its own.

Step 10: Chill Again

Back into the refrigerator for another 2 hours, or until the ganache is set and the whole cake is firm.

Step 11: Serve

When you’re ready to serve, run a warm knife around the inside edges of the springform pan, then release the sides. For picture-perfect slices, warm your knife under hot water, dry it completely, and make your cut.

You Must Know

The cake MUST be completely cool before you add the mousse layer. I cannot stress this enough! Even slightly warm cake will melt your mousse and ruin the layers. If you’re impatient like me, you can pop the cooled cake in the fridge for 30 minutes to speed things up.

Personal Secret: I always use chocolate bars instead of chips for the mousse and ganache. Chips contain stabilizers that prevent them from melting as smoothly, and you want that silky texture.

Pro Tips & Cooking Hacks

Don’t over-whip the cream for the mousse! Stop at soft peaks. Over-whipped cream will give you a grainy, butter-like texture instead of that dreamy, melt-in-your-mouth mousse.

Room temperature egg mixes into the cake batter more smoothly and creates a better crumb structure. Just let it sit on the counter for 20 minutes before you start.

Folding technique matters: When adding chocolate to whipped cream, use a gentle lifting and turning motion. Stirring vigorously will deflate all those air bubbles you worked to create.

Common mistake to avoid: Don’t skip the parchment paper in the bottom of the pan! Even with a springform, the cake can stick. That parchment circle is your insurance policy.

Smart shortcut: Make the cake base the night before and leave it in the pan, covered with plastic wrap. The next day, you’ll just need to whip up the mousse and ganache – so much easier!

Flavor Variations & Suggestions

Want to make this cake your own? Here are some fun twists:

Espresso Chocolate Mousse Cake: Add 1 tablespoon of instant espresso powder to the cake batter and 1 teaspoon to the mousse. The coffee enhances the chocolate flavor without making it taste like coffee.

White Chocolate Raspberry: Use white chocolate for the mousse layer and swirl in some raspberry puree. Top with white chocolate ganache and fresh raspberries.

Mint Chocolate Dream: Add 1/2 teaspoon peppermint extract to the mousse layer. Garnish with crushed chocolate mint candies or Andes mints.

Orange Chocolate Elegance: Add 1 tablespoon of orange zest to the mousse and a splash of Grand Marnier if you’re feeling fancy. It’s like a chocolate orange in cake form!

Peanut Butter Swirl: Warm 1/4 cup of peanut butter until it’s pourable, drizzle it over the mousse layer, and swirl with a knife before adding the ganache.

Make-Ahead Options

This is actually the PERFECT make-ahead dessert! Here’s how to plan it:

Day Before: Make the entire cake through step 11 and keep it refrigerated. It actually tastes even better the next day because the flavors meld together beautifully.

Two Days Before: You can bake just the cake base, let it cool completely, wrap it tightly in plastic wrap (still in the pan), and refrigerate. Add the mousse and ganache the day before you need it.

Freezing: The cake base alone freezes beautifully for up to 2 months. Wrap it tightly in plastic wrap, then foil. Thaw in the fridge overnight before adding the mousse. I don’t recommend freezing the assembled cake – the mousse texture changes and can become a bit grainy.

Morning of: If you’re serving this for dinner, make it in the morning and let it chill all day. It needs at least 4 hours total chill time to set properly.

Recipe Notes & Baker’s Tips

About chocolate percentage: The 60-70% cocoa range gives you rich chocolate flavor without being bitter. If you prefer sweeter, go with 55-60%. Above 70% can be too intense for some people.

Springform pan size matters: This recipe is designed for a 9-inch pan. An 8-inch will be very tall (and might overflow), while a 10-inch will be quite flat.

Ganache consistency: If your ganache seems too thick to pour, let it sit at room temperature for 5 minutes. Too thin? Pop it in the fridge for 10 minutes, stirring occasionally until it thickens slightly.

The thin batter is normal! I get questions about this every time. When you add the hot water, the batter will look incredibly thin. This is exactly right – it bakes into the most tender, moist cake.

Folding wisdom: When you’re folding chocolate into whipped cream, work quickly but gently. The chocolate will start to set as it cools, so don’t let it sit too long before folding.

Serving Suggestions

This chocolate mousse cake is stunning enough to stand alone, but here are some ways to make it even more special:

Serve each slice with a dollop of freshly whipped cream and a few fresh raspberries or strawberries on the side. The tartness of berries cuts through the richness perfectly.

For an elegant touch, dust the plate with cocoa powder using a small sieve, or drizzle some raspberry or caramel sauce in an artistic pattern.

A small scoop of vanilla bean ice cream melting beside a slice is pretty much heaven on a plate.

When to serve: This is perfect for birthdays, anniversaries, dinner parties, or any time you want to impress. It’s fancy enough for special occasions but beloved enough to make “just because.”

Garnish ideas: Chocolate shavings, fresh mint leaves, gold leaf for extra elegance, or even some crushed toffee bits for texture contrast.

How to Store Your Chocolate Mousse Cake

Refrigerator: This cake must be stored in the refrigerator because of the mousse and ganache layers. Cover it loosely with plastic wrap or a cake dome (make sure the wrap doesn’t touch the ganache surface or it’ll stick and mess up that pretty finish). It keeps beautifully for up to 4 days.

Room Temperature: Not recommended! The mousse layer will start to soften and potentially separate after an hour or so at room temperature.

Freezer: I don’t recommend freezing the completed cake. The mousse texture becomes grainy and weepy when thawed. If you need to freeze something, freeze just the baked cake base as mentioned in the make-ahead section.

Reheating: No reheating needed – this cake is meant to be served chilled! Just remove it from the fridge about 10-15 minutes before serving to take the edge off the cold, which allows the flavors to shine through.

Individual slices: Already sliced the cake? Wrap individual pieces in plastic wrap and store in an airtight container for up to 4 days. They actually travel pretty well if you need to pack a lunch dessert!

Allergy Information

Contains: Dairy (milk, heavy cream), eggs, gluten (wheat flour), and depending on your chocolate choice, may contain soy lecithin.

Dairy-Free Option: Use almond milk or oat milk in the cake, and coconut cream (the thick part from a can of full-fat coconut milk) in place of heavy cream. Make sure your chocolate is dairy-free. The texture will be slightly different but still delicious!

Gluten-Free: Replace the all-purpose flour with a 1:1 gluten-free baking flour blend. Make sure it contains xanthan gum for the best structure.

Egg-Free: You can try a flax egg (1 tablespoon ground flaxseed + 3 tablespoons water, let sit 5 minutes) in the cake base, though the texture will be a bit denser.

Nut-Free: This recipe is naturally nut-free! Just make sure your chocolate doesn’t have “may contain nuts” warnings if this is for someone with severe allergies.

Questions I Get Asked A Lot

Can I use milk chocolate instead of dark chocolate?

You can, but I’d reduce the powdered sugar in the mousse to 2 tablespoons since milk chocolate is already much sweeter. The mousse might also be a bit softer. I find the dark chocolate gives that sophisticated, not-too-sweet balance that makes this cake so crave-worthy!

My mousse deflated when I folded in the chocolate, what happened?

This usually means the chocolate was too hot when you added it, which melted the whipped cream, or you stirred instead of folded. Make sure your melted chocolate has cooled to barely warm (test it on your wrist – it should feel just slightly warm, like bathwater). Then fold gently, not stir!

Can I make this without a springform pan?

Technically yes, but it’s MUCH harder to serve beautifully. You could use a regular 9-inch round cake pan lined with parchment on the bottom and sides, then lift the whole thing out using the parchment. Just know that your slices won’t be as clean and pretty.

How far in advance can I make this?

The sweet spot is 1-2 days ahead! Made the day before, it’s absolutely perfect. You can make it up to 3 days ahead, but the cake base starts to dry out slightly after that. If I’m making it more than a day ahead, I actually wait to add the ganache layer until the day before serving so it’s extra glossy.

💬 Tried this recipe? Leave a comment and rating below! I’d love to hear how your chocolate mousse cake turned out, and if you tried any fun variations!