I made a Chocolate Mousse Cake with dark cocoa powder, an easy chocolate mousse center, and a chocolate ganache cover, and I use one small trick that reliably holds it together.

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I can’t stop thinking about this Dark Chocolate Mousse, it looks like something from a pastry shop but it’s not precious, it has attitude. Rich dark unsweetened cocoa powder gives it that almost bitter backbone, and a bit of hot brewed coffee pulls the chocolate into focus like a flashlight.

It’s equal parts drama and comfort, the kind of Chocolate you brag about and then hide a slice for later. Call it a Mousse Cake if you want, though really it steals the room every time.

I messed up a bunch before getting here, but this one finally felt right.

Ingredients

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Bitter cocoa powder, antioxidant rich, adds chocolate flavor, some fiber, low sugar not very sweet.
Dark chocolate, high in fat and carbs, provides antioxidants, intense sweetness and creamy texture.
Sugar, pure carbs that give sweetness and structure, empty calories if used too much, addictive.
All purpose flour, main source carbs, gives structure and bulk, low in micronutrients unless enriched.
Eggs, protein rich, help bind and leaven, good nutrients like choline and vitamins.
Heavy cream, high fat, gives richness and mouthfeel, supplies calories and some vitamin A.
Hot coffee, adds depth and enhances chocolate, virtually no calories, slightly bitter not sour.

Ingredient Quantities

For the cake:

2 cups (400 g) granulated sugar

1 3/4 cups (220 g) all purpose flour

3/4 cup (75 g) dark unsweetened cocoa powder, preferably Dutch process

1 1/2 teaspoons baking powder

1 1/2 teaspoons baking soda

1 teaspoon salt

2 large eggs, room temp

1 cup (240 ml) whole milk

1/2 cup (120 ml) vegetable oil

2 teaspoons vanilla extract

1 cup (240 ml) hot brewed coffee or hot water

For the chocolate mousse:

12 oz (340 g) good quality dark chocolate (60 to 70 percent), finely chopped

2 cups (480 ml) heavy whipping cream, cold, divided

2 tablespoons granulated sugar or powdered sugar, optional

1 teaspoon vanilla extract

1 teaspoon unflavored powdered gelatin plus 2 tablespoons water, optional for extra stability

For the ganache:

8 oz (225 g) dark chocolate, chopped

3/4 cup (180 ml) heavy cream

1 tablespoon unsalted butter, room temp, optional for shine

Pinch of fine salt

How to Make this

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1. Preheat oven to 350 F (175 C). Grease and line two 9 inch round pans. Sift together 2 cups sugar, 1 3/4 cups flour, 3/4 cup dark cocoa powder, 1 1/2 tsp baking powder, 1 1/2 tsp baking soda and 1 tsp salt into a bowl so there are no lumps.

2. In another bowl whisk 2 large room temp eggs, 1 cup whole milk, 1/2 cup vegetable oil and 2 tsp vanilla until combined. Pour wet into dry and stir until just smooth, don’t overmix or the cake will be dense.

3. Stir in 1 cup hot brewed coffee or hot water (this blooms the cocoa and makes the cake extra chocolatey). Divide batter between pans, tap to release big air bubbles and bake 30 to 35 minutes or until a toothpick comes out with a few moist crumbs. Cool 10 minutes in pans, then turn out to cool completely on a rack.

4. For the mousse chop 12 oz dark chocolate finely. If using gelatin, sprinkle 1 tsp unflavored powdered gelatin over 2 tbsp cold water to bloom and set aside.

5. Heat 1/2 cup of the heavy cream until just simmering, pour over the chopped chocolate and let sit 1 minute, then stir until smooth. If using gelatin, melt it briefly and stir into the chocolate mixture now. Stir in 1 tsp vanilla and 2 tbsp sugar if you like it sweeter. Let the chocolate mix cool to lukewarm.

6. Whip the remaining 1 1/2 cups cold heavy cream to soft/medium peaks (don’t go to stiff or it will be hard to fold). Fold a quarter of the whipped cream into the chocolate to lighten it, then gently fold in the rest until uniform. Cover and chill until thick enough to spread, about 30 to 60 minutes.

7. Prepare the ganache by placing 8 oz chopped dark chocolate in a bowl. Heat 3/4 cup heavy cream until it just simmers, pour over the chocolate, let sit 1 minute then stir until glossy and smooth. Stir in 1 tbsp room temp butter and a pinch of fine salt for shine and balance. Cool until pourable but not super runny.

8. Level the cake layers if needed. Put one layer on your serving plate, spread about half the mousse evenly to the edge (use an offset spatula), then chill 20 to 30 minutes so the mousse firms a bit and won’t ooze.

9. Top with the second cake layer, press lightly, do a quick crumb coat with a thin layer of mousse if you want cleaner edges and chill 10 to 15 minutes.

10. Pour the ganache over the chilled cake, letting it drip down the sides, smooth the top quickly with an offset spatula. Refrigerate at least 1 hour to set everything. Take cake from fridge 20 to 30 minutes before serving so the mousse softens a little.

Equipment Needed

1. Two 9-inch round cake pans, greased and lined with parchment paper
2. Oven (preheat to 350 F / 175 C)
3. Mixing bowls (2 to 3: dry, wet, and one for mousse)
4. Sifter or fine-mesh sieve to remove lumps from the dry ingredients
5. Whisk and silicone spatula for mixing and gentle folding
6. Electric hand mixer or stand mixer with whisk attachment to whip the cream
7. Heatproof bowls plus a small saucepan for heating cream and melting chocolate (or microwave-safe bowls) — dont overheat chocolate
8. Offset spatula and serrated knife or bench scraper to level layers and spread mousse
9. Cooling rack and cake board or serving plate, plus a toothpick or cake tester

FAQ

Q: Can I skip the gelatin in the mousse?

A: Yes, you can skip it. The mousse will still set if you fold in properly whipped cream and chill it long enough, but it will be softer and less stable, especially in warm kitchens. If you need it for a party or transport, use the gelatin (bloom it in the water, melt gently and stir into warm chocolate) for extra hold.

Q: My mousse is runny after chilling, what went wrong?

A: Most likely the whipped cream was under-whipped or the chocolate was too hot when folded in and knocked down the air. Make sure cream reaches soft to medium peaks, let melted chocolate cool slightly before folding, and fold gently with big strokes so you don't deflate it. If it's still loose, try folding in a little extra whipped cream or use a touch of bloomed gelatin warmed and mixed in.

Q: How do I keep the cake moist and not dry out?

A: Don’t overbake it. Check a few minutes before the recipe time with a toothpick in the center it should come out with a few moist crumbs. Also brush each layer lightly with simple syrup or the hot coffee from the recipe for extra moisture and deeper flavor. Let layers cool fully before stacking so the mousse and ganache stay smooth.

Q: What chocolate should I use for the mousse and ganache?

A: Use good quality dark chocolate in the 60 to 70% range for balance of bitterness and creaminess. Avoid cheap compound chocolates that list vegetable oil instead of cocoa butter they change texture and flavor. Finely chop the chocolate so it melts evenly and quickly.

Q: My ganache looks dull or seized, how do I fix it?

A: If it looks dull but smooth, stir in the room temp butter at the end for shine. If it seizes and becomes grainy, warm a few tablespoons of cream, whisk it in slowly, or briefly blend with an immersion blender to smooth it out. Straining helps remove stubborn bits before pouring over the cake.

Q: How long can I store the finished cake and can I freeze it?

A: Store the assembled cake in the fridge for up to 3 days, loosely covered so the ganache doesn't sweat. Bring to room temp 30 to 60 minutes before serving for best texture. You can freeze the cake for up to a month wrapped well, but results are best if you freeze layers or mousse separately then assemble after thawing.

Dark Chocolate Mousse Cake Recipe Substitutions and Variations

Whole milk
- Buttermilk – swap 1:1 for a tangier, more tender crumb; if your recipe already uses baking soda it helps with rise.
- Unsweetened almond or oat milk – 1:1 for a dairy free option, cake will be a little lighter.
- Full fat canned coconut milk (chilled, scoop the cream) – use slightly less by volume if very thick, adds richness and a hint of coconut.
Vegetable oil
- Melted unsalted butter – 1:1 for richer flavor, cake crumb will be firmer and tastier.
- Light olive oil or avocado oil – 1:1, both give good results but olive oil may add a mild fruity note.
- Applesauce – replace half to all of the oil (1:1) to cut fat and add moisture, cake will be denser and slightly sweeter.
Eggs
- Flax “egg” – 1 tbsp ground flax + 3 tbsp water per egg, let sit 5 min; good binder, but less lift than real eggs.
- Applesauce or mashed banana – 1/4 cup per egg, gives moisture and sweetness, better for denser cakes.
- Commercial egg replacer (like Ener-G) – follow package directions, works well for structure in cakes.
Heavy cream (for mousse/ganache)
- Chilled full fat coconut cream – 1:1 for a dairy free mousse, will add coconut flavor and firm up when cold.
- Mascarpone or cream cheese thinned with a little milk – use to add richness and body, whip to lighten for mousse.
- Aquafaba (chickpea brine) – whipped to stiff peaks and folded in for a vegan, airy mousse; flavor and texture differ a bit from dairy cream.

Pro Tips

1. Chill and prep like a pro: put your mixing bowl and beaters in the fridge for 10 minutes before whipping cream, and chill the cake layers so the mousse firms fast when you layer it, otherwise it will ooze everywhere. Also line pans with parchment that hangs over the edges a bit so you can lift layers out cleanly.

2. Temper and timing for mousse: let the melted chocolate cool until just lukewarm before folding in whipped cream, or you’ll deflate it. Fold in gently with a big motion so you keep as much air as possible. If you need the mousse to hold up for a party or warm room, bloom a teaspoon of gelatin in the water and melt it into the chocolate first.

3. Ganache control: pour ganache when it is pourable but not scorching hot, that way it will run down the sides and set with a nice shine. If it’s too thick warm it briefly over a bowl of hot water, if too thin let it chill a few minutes and stir to thicken. A little room temp butter worked in at the end gives an extra glossy finish.

4. Slicing and serving tricks: take the cake out of the fridge 20 to 30 minutes before serving so the mousse softens a bit, then use a knife warmed under hot water and wiped dry between cuts for clean slices. Store covered in the fridge up to a few days, and if you need to freeze slices wrap tightly and thaw in the fridge.

Dark Chocolate Mousse Cake Recipe

Recipe by Louise Nightin

0.0 from 0 votes

I made a Chocolate Mousse Cake with dark cocoa powder, an easy chocolate mousse center, and a chocolate ganache cover, and I use one small trick that reliably holds it together.

Servings

servings

Calories

787

kcal

Equipment: 1. Two 9-inch round cake pans, greased and lined with parchment paper
2. Oven (preheat to 350 F / 175 C)
3. Mixing bowls (2 to 3: dry, wet, and one for mousse)
4. Sifter or fine-mesh sieve to remove lumps from the dry ingredients
5. Whisk and silicone spatula for mixing and gentle folding
6. Electric hand mixer or stand mixer with whisk attachment to whip the cream
7. Heatproof bowls plus a small saucepan for heating cream and melting chocolate (or microwave-safe bowls) — dont overheat chocolate
8. Offset spatula and serrated knife or bench scraper to level layers and spread mousse
9. Cooling rack and cake board or serving plate, plus a toothpick or cake tester

Ingredients

For the cake:
2 cups (400 g) granulated sugar
1 3/4 cups (220 g) all purpose flour
3/4 cup (75 g) dark unsweetened cocoa powder, preferably Dutch process
1 1/2 teaspoons baking powder
1 1/2 teaspoons baking soda
1 teaspoon salt
2 large eggs, room temp
1 cup (240 ml) whole milk
1/2 cup (120 ml) vegetable oil
2 teaspoons vanilla extract
1 cup (240 ml) hot brewed coffee or hot water
For the chocolate mousse:
12 oz (340 g) good quality dark chocolate (60 to 70 percent), finely chopped
2 cups (480 ml) heavy whipping cream, cold, divided
2 tablespoons granulated sugar or powdered sugar, optional
1 teaspoon vanilla extract
1 teaspoon unflavored powdered gelatin plus 2 tablespoons water, optional for extra stability
For the ganache:
8 oz (225 g) dark chocolate, chopped
3/4 cup (180 ml) heavy cream
1 tablespoon unsalted butter, room temp, optional for shine
Pinch of fine salt

Directions

Preheat oven to 350 F (175 C). Grease and line two 9 inch round pans. Sift together 2 cups sugar, 1 3/4 cups flour, 3/4 cup dark cocoa powder, 1 1/2 tsp baking powder, 1 1/2 tsp baking soda and 1 tsp salt into a bowl so there are no lumps.
In another bowl whisk 2 large room temp eggs, 1 cup whole milk, 1/2 cup vegetable oil and 2 tsp vanilla until combined. Pour wet into dry and stir until just smooth, don't overmix or the cake will be dense.
Stir in 1 cup hot brewed coffee or hot water (this blooms the cocoa and makes the cake extra chocolatey). Divide batter between pans, tap to release big air bubbles and bake 30 to 35 minutes or until a toothpick comes out with a few moist crumbs. Cool 10 minutes in pans, then turn out to cool completely on a rack.
For the mousse chop 12 oz dark chocolate finely. If using gelatin, sprinkle 1 tsp unflavored powdered gelatin over 2 tbsp cold water to bloom and set aside.
Heat 1/2 cup of the heavy cream until just simmering, pour over the chopped chocolate and let sit 1 minute, then stir until smooth. If using gelatin, melt it briefly and stir into the chocolate mixture now. Stir in 1 tsp vanilla and 2 tbsp sugar if you like it sweeter. Let the chocolate mix cool to lukewarm.
Whip the remaining 1 1/2 cups cold heavy cream to soft/medium peaks (don't go to stiff or it will be hard to fold). Fold a quarter of the whipped cream into the chocolate to lighten it, then gently fold in the rest until uniform. Cover and chill until thick enough to spread, about 30 to 60 minutes.
Prepare the ganache by placing 8 oz chopped dark chocolate in a bowl. Heat 3/4 cup heavy cream until it just simmers, pour over the chocolate, let sit 1 minute then stir until glossy and smooth. Stir in 1 tbsp room temp butter and a pinch of fine salt for shine and balance. Cool until pourable but not super runny.
Level the cake layers if needed. Put one layer on your serving plate, spread about half the mousse evenly to the edge (use an offset spatula), then chill 20 to 30 minutes so the mousse firms a bit and won't ooze.
Top with the second cake layer, press lightly, do a quick crumb coat with a thin layer of mousse if you want cleaner edges and chill 10 to 15 minutes.
Pour the ganache over the chilled cake, letting it drip down the sides, smooth the top quickly with an offset spatula. Refrigerate at least 1 hour to set everything. Take cake from fridge 20 to 30 minutes before serving so the mousse softens a little.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.