Ingredients:
- 1/2 cup (115g) unsalted butter, softened
- 3/4 cup (150g) granulated sugar
- 2 large eggs
- 1 tsp (5ml) vanilla extract
- 1 cup (125g) all-purpose flour
- 1/3 cup (30g) Dutch-process cocoa powder
- 1/2 tsp (3g) baking soda
- 1/4 tsp (1.5g) salt
- 1/2 cup (120ml) buttermilk
- 6 oz (170g) dark chocolate (60% cocoa), chopped
- 3 cups (720ml) heavy whipping cream, divided
- 3 tbsp (45g) powdered sugar, divided
- 6 oz (170g) milk chocolate, chopped
- 6 oz (170g) white chocolate, chopped
- 1 tsp (5ml) vanilla bean paste
- 4 oz (115g) semi-sweet chocolate, chopped
- 1/2 cup (120ml) heavy cream
- 1 tbsp (15g) unsalted butter, room temperature
Instructions:
- Preheat oven to 350°F (175°C). Grease and line the bottom of a 9-inch springform pan with parchment paper.
- Cream the softened butter and granulated sugar until pale, then beat in eggs and vanilla extract.
- Sift together flour, cocoa powder, baking soda, and salt. Alternately add dry ingredients and buttermilk into the butter mixture, stirring until combined.
- Pour batter into the pan and bake for 18 minutes until a toothpick comes out clean. Cool completely in the pan.
- For the dark chocolate layer: Melt 170g dark chocolate with 1/4 cup (60ml) warmed cream. Let cool slightly.
- Whip 3/4 cup (180ml) cream and 2 tbsp powdered sugar to soft peaks, then gently fold into the dark chocolate mixture.
- Spread dark mousse over the cooled sponge base and refrigerate.
- Repeat the process for the milk chocolate layer using 170g milk chocolate, 1/4 cup warmed cream, and the remaining 1 tbsp powdered sugar with 3/4 cup whipped cream.
- Repeat the process for the white chocolate layer using 170g white chocolate, 1/4 cup warmed cream, vanilla bean paste, and 3/4 cup whipped cream.
- Chill the assembled cake for at least 6 hours to set.
- Prepare the finish: Melt 115g semi-sweet chocolate with 120ml heavy cream and 15g butter until smooth. Pour over the chilled cake and smooth with an offset spatula.