Description
If you’re a die-hard chocolate fan (like, spoon-straight-into-the-ganache level), you’re about to fall hard for this ultra-creamy chocolate mousse cake. It’s layered with intense chocolate flavor, silky mousse, and topped with a dreamy ganache that takes the whole thing to “how is this even homemade?” status.
Ingredients
Scale
Chocolate Cake Layer:
- 1 cup (125g) plain flour
- 6 tbsp (40g) Dutch-process cocoa
- ½ tsp baking soda
- 1 tsp baking powder
- ¼ tsp fine sea salt
- ¾ cup (150g) white sugar
- 1 large egg + 1 yolk
- 1 tsp vanilla extract
- ⅓ cup (80ml) oil (vegetable or canola)
- ⅓ cup (80g) sour cream
- ⅓ cup (80ml) buttermilk
- ½ cup (120ml) hot brewed espresso or strong coffee
Chocolate Mousse Filling:
- 7 oz (200g) dark chocolate (around 60% cocoa)
- 3 tbsp (24g) powdered sugar
- 1 tsp vanilla extract
- 4 oz (120ml) heavy cream (for melting chocolate)
- 1¾ cups (420ml) heavy cream (for whipping)
- 2½ tbsp (16g) cocoa powder
- 6g unflavored gelatin
- 40g cold water
Ganache Topping:
- 5 oz (140g) dark chocolate
- 5 oz (140ml) heavy cream
Instructions
- Bake the Cake Base
- Preheat your oven to 350°F (180°C). Grease and line a 9-inch springform pan with parchment.
- In a large bowl, whisk eggs, vanilla, sour cream, oil, and buttermilk until smooth. Mix in the sugar.
- Sift in the cocoa powder, flour, baking powder, soda, and salt. Stir gently until just combined.
- Slowly stir in the hot espresso – the batter will thin out a bit and get glossy.
- Pour it into your prepared pan and bake for 22–25 minutes. When a toothpick comes out with a few crumbs, it’s done.
- Let it cool fully on a wire rack before adding the mousse layer.
- Whip Up the Mousse
- In a small bowl, stir gelatin and water together and let it sit (bloom) for 10 minutes.
- Meanwhile, melt dark chocolate with the 4 oz cream either in the microwave (short 15-second bursts) or over a double boiler. Let it cool slightly.
- In another bowl, whip the remaining heavy cream with cocoa, sugar, and vanilla until soft peaks form.
- Melt the bloomed gelatin in the microwave (about 10 seconds), stir it into the warm chocolate, and mix well.
- To avoid deflating the cream, mix in a spoonful of the whipped mixture first. Then fold in the rest until smooth and airy.
- Assemble the Cake
- If the cake domed while baking, level it with a serrated knife.
- Place the cake layer back in the springform pan and line the inside with parchment or acetate for clean edges.
- Spread the mousse evenly over the cake and smooth the top.
- Chill for at least 6 hours—overnight is even better.
- Ganache Time
- Combine the chocolate and cream in a heat-safe bowl and microwave for 60 seconds. Let it sit 10 minutes, then stir until silky.
- If needed, microwave for a few more seconds to thin it out, or cool slightly to thicken.
- Once the mousse is firm, pour ganache over the top and gently spread to the edges.
- Chill again for 30 minutes so the ganache sets.
- Slice and Serve
- Run a sharp knife under hot water and dry it before each slice for clean layers.
- Serve cold and store leftovers covered in the fridge.
Notes
Tips & Tricks
- Sift the cocoa to prevent dry lumps in your batter or mousse.
- Be gentle with the mousse — over-mixing can knock out the air.
- Let everything cool before layering, or you’ll risk a melting mousse disaster.
- Use a serrated knife and clean it between slices for that bakery-worthy look.
Want to turn this into mini desserts? Use silicone molds or dessert rings for individual mousse cakes!
- Prep Time: 40 minutes
- Chilling Time: 6 hours
- Cook Time: 25 minutes
- Category: Desserts
Nutrition
- Calories: 485kcal