Indulge in this luscious chocolate mousse cake that combines a moist, rich chocolate base with airy, creamy mousse and a silky ganache topping.
Beyond its decadent taste, it’s made with wholesome ingredients like dark chocolate and eggs, providing good fats and a touch of protein.
Perfectly portioned and satisfying, it’s an ideal dessert for everyday treats or special occasions.
Chocolate Mousse Cake
Equipment
- 1 × 9″ Springform Pan
- 1 × Mixing Bowls (various sizes)
- 1 × Saucepan
- 1 × Whisk
- 1 × Rubber Spatula
- 1 × Hand or Stand Mixer
- 1 × Parchment Paper or Cake Collar (acetate)
- 1 × Knife or Cake Leveler
- 1 × Measuring Cups & Spoons
- 1 × Heat-Safe Bowl
Ingredients
Chocolate Cake
- ¾ cup 95g all-purpose flour (or gluten-free baking flour)
- 2 tbsp cornstarch
- ¼ cup 25g Dutch-process cocoa powder
- 1 tsp baking soda
- ½ tsp baking powder
- ¼ tsp kosher salt
- ½ cup 100g fine granulated sugar
- ½ cup 105g packed dark brown sugar
- ½ cup 112g vegetable or olive oil
- 2 large eggs
- 1 tsp vanilla extract
- ½ cup 120g sour cream
- ½ cup 120g hot coffee
Chocolate Cake Soak
- ½ cup 120g hot coffee
- 1 tbsp Dutch-process cocoa powder
Chocolate Mousse
- 7 oz 200g 70% dark chocolate, chopped
- 7 oz 200g milk chocolate, chopped
- 3 large egg yolks
- 3 large egg whites
- 3 tbsp water
- 1 ½ tsp unflavored gelatin
- 1 ¾ cups 420ml heavy cream, divided
- ½ tsp cream of tartar
- ¼ cup 50g fine granulated sugar
Chocolate Ganache
- 6 oz 170g 70% dark chocolate, chopped
- ¾ cup 180ml heavy cream
Instructions
- Prepare the Pan: Start by greasing the inside of a 9-inch springform pan with a thin layer of butter or non-stick spray. Cut a round piece of parchment paper to fit the bottom of the pan and place it inside. Reattach the springform ring on top, making sure the parchment sticks slightly out around the edges. This will help release the cake cleanly later.
- Combine Dry Ingredients for the Cake: In a medium mixing bowl, whisk together 3/4 cup all-purpose flour (or gluten-free flour), 2 tablespoons cornstarch, 1/4 cup Dutch-process cocoa powder, 1 teaspoon baking soda, 1/2 teaspoon baking powder, and 1/4 teaspoon kosher salt. Make sure the ingredients are evenly mixed and free of lumps. Set aside while you prepare the wet ingredients.
- Mix Wet Ingredients for the Cake: In a large mixing bowl, combine 1/2 cup fine granulated sugar, 1/2 cup packed dark brown sugar, and 1/2 cup vegetable or olive oil. Whisk together until the mixture looks like damp sand. Add 2 large eggs and 1 teaspoon vanilla extract, whisking until fully incorporated. Fold in 1/2 cup sour cream until smooth.
- Combine Wet and Dry Ingredients: Add the dry ingredient mixture to the wet ingredients in two batches. Stir gently until it’s halfway combined. Then pour in 1/2 cup of hot coffee and whisk until smooth. The batter will be thin, almost pourable, which is normal and ensures a moist cake.
- Bake the Cake: Pour the batter into the prepared springform pan. Smooth the top with a spatula for an even surface. Bake in a preheated 350°F (175°C) oven for 25–30 minutes, or until a toothpick inserted in the center comes out clean but with a few moist crumbs attached. Avoid overbaking to keep the cake soft.
- Cool and Level the Cake: Allow the cake to cool completely at room temperature or in the refrigerator. Once cooled, remove the springform ring and trim the top of the cake with a knife or cake leveler so it is flat and even. Place the springform ring back around the cake and line the inner sides with an acetate strip or parchment paper to create a smooth edge for the mousse layer.
- Prepare the Chocolate Cake Soak: In a small bowl, mix 1/2 cup hot coffee with 1 tablespoon Dutch-process cocoa powder until smooth. Spoon the mixture evenly over the cake surface, ensuring every part of the cake is lightly soaked. Set aside while preparing the mousse.
- Melt the Chocolate for Mousse: Chop 7 oz dark chocolate and 7 oz milk chocolate and place in a heat-safe bowl. Set the bowl over a saucepan with gently simmering water, making sure the bowl doesn’t touch the water. Stir occasionally until the chocolate melts completely and is smooth. Remove from heat and allow it to cool slightly.
- Incorporate Egg Yolks into Chocolate: Once the melted chocolate has cooled slightly, whisk in the 3 egg yolks one at a time. The mixture will thicken noticeably, but this is expected. Set aside while preparing the gelatin.
- Bloom the Gelatin: In a small bowl, combine 3 tablespoons water with 1 1/2 teaspoons unflavored gelatin. Let it sit for a few minutes until it absorbs the water and turns translucent.
- Heat the Cream for Gelatin: Pour 3/4 cup of heavy cream into the cleaned saucepan. Heat over medium-low until it is steaming but not boiling. Add the bloomed gelatin to the hot cream and whisk until fully dissolved.
- Combine Chocolate and Cream: Pour half of the hot cream and gelatin mixture into the chocolate-egg yolk mixture. Whisk until smooth and glossy, then add the remaining cream. The resulting mousse base should be smooth, shiny, and pudding-like in consistency.
- Whip the Heavy Cream: In a clean large mixing bowl, whip the remaining 1 cup of heavy cream on high speed until it forms stiff peaks. Set aside for folding into the chocolate mixture.
- Prepare the Meringue: In another clean, dry mixing bowl, combine 3 large egg whites with 1/2 teaspoon cream of tartar. Whip on high speed until foamy. Gradually add 1/4 cup sugar while continuing to whip until soft peaks form. The meringue should hold its shape but have a slight droop at the tip.
- Fold Whipped Cream into Chocolate: Using a rubber spatula, gently fold the whipped cream into the chocolate mixture until fully combined. Be careful not to deflate the cream; fold slowly in a circular motion, scraping the sides of the bowl.
- Fold Meringue into Chocolate: Next, gently fold the meringue into the chocolate mixture in thirds. Use light, sweeping motions to maintain the airy texture. Continue folding until the mousse is a uniform chocolate color with no streaks, pourable but still light.
- Assemble the Cake: Pour the mousse evenly over the soaked chocolate cake. Smooth the top with a spatula and chill in the refrigerator for at least 4 hours, ideally overnight, until set.
- Prepare the Ganache: Chop 6 oz dark chocolate and place in a heatproof bowl. Heat 3/4 cup heavy cream in a microwave or on the stove until hot and bubbling, then pour over the chocolate. Let it sit for 3 minutes, then whisk until smooth and glossy.
- Apply Ganache: Remove the cake from the refrigerator and release the springform ring. Peel away the acetate or parchment lining. Pour the ganache over the center of the cake, spreading it carefully to the edges with a spoon or offset spatula, allowing a few drips to fall naturally down the sides.
- Chill and Serve: Chill the cake for an additional 30 minutes to allow the ganache to set completely. Use a sharp knife to slice into 8–10 generous pieces. Serve as a luxurious dessert for celebrations or a special everyday treat.
Notes
- Cake Batter Consistency: The batter will be thin, which is normal. This ensures a moist cake base.
- Chocolate Choice: Use high-quality dark and milk chocolate for a richer, smoother mousse and ganache.
- Gelatin Use: Ensure the gelatin blooms properly in water before adding to the cream to prevent lumps.
- Acetate vs. Parchment: Acetate creates cleaner sides for the mousse layer, but parchment paper works as a substitute.
- Chilling Time: Allow the mousse to set for at least 4 hours or overnight for best texture.
- Ganache Drips: Pour slowly and let gravity create natural drips for a professional look.
- Cake Slicing: Use a hot, clean knife for neat slices. Wipe the knife between cuts.
Chef’s Secrets For Perfect Texture
Achieving a light and airy chocolate mousse requires careful folding techniques.
Always fold the whipped cream and meringue gently into the chocolate mixture to preserve the airiness.
Avoid overmixing, as this can deflate the mousse and result in a denser texture.
For a glossy ganache, ensure the cream is hot but not boiling before pouring it over the chocolate.
Using a cake collar or acetate sheet will also help achieve smooth, professional-looking edges that hold the mousse perfectly in place.
Serving Suggestions For Elegant Presentation
This chocolate mousse cake pairs beautifully with fresh berries, a dusting of cocoa powder, or a sprinkle of edible gold for a special occasion.
Serve slices with a dollop of lightly whipped cream or a scoop of vanilla ice cream for contrast.
A drizzle of raspberry or salted caramel sauce can enhance the flavor layers.
For a more casual presentation, serve on a simple white plate to highlight the rich, glossy ganache and airy mousse.
Storage Tips To Maintain Freshness
Store the cake in the refrigerator, covered loosely with plastic wrap or inside a cake container, to prevent the mousse from absorbing other odors.
It will stay fresh for up to 3 days. For longer storage, individual slices can be frozen for up to 1 month; wrap them tightly in plastic wrap and then foil.
Thaw slices in the refrigerator for several hours before serving.
Avoid leaving the cake at room temperature for extended periods, as the mousse may lose its firmness.
Frequently Asked Questions
1. Can I make this cake ahead of time?
Yes! This cake is ideal for making a day or two in advance. Prepare the cake, mousse, and ganache, then refrigerate until serving. Chilling overnight enhances the flavors and allows the mousse to set perfectly.
2. Can I use only dark chocolate for the mousse?
Absolutely. Using only dark chocolate will create a richer, slightly more bitter mousse. Adjust the sweetness if desired by slightly increasing the sugar in the meringue.
3. How do I prevent the ganache from seizing?
Ensure the cream is hot but not boiling before pouring over the chocolate. Stir gently and slowly until smooth. Avoid introducing cold ingredients directly into the chocolate, as this may cause it to seize.
4. Can I make this cake gluten-free?
Yes, substitute the all-purpose flour with a gluten-free baking flour blend. Ensure the blend contains xanthan gum or another binding agent to maintain the cake’s structure.
5. What’s the best way to slice the cake cleanly?
Use a sharp knife dipped in hot water and wiped dry before each cut. Slice slowly in a single motion to prevent dragging the mousse and ganache, which ensures neat, professional-looking pieces.
