Ingredients
Equipment
Method
- Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan, or line the bottom with parchment paper and grease the sides.
- In a large bowl, whisk together the flour, granulated sugar, cocoa powder, baking soda, and salt. Ensure there are no lumps.1 ½ cups all-purpose flour, 1 cup granulated sugar, ⅓ cup unsweetened cocoa powder, 1 teaspoon baking soda, ½ teaspoon salt
- In a separate medium bowl, whisk together the buttermilk, vegetable oil, egg, and vanilla extract until well combined.1 cup buttermilk, ½ cup vegetable oil, 1 large egg, 1 teaspoon vanilla extract
- Pour the wet ingredients into the dry ingredients and mix on low speed (or by hand with a whisk) until just combined. Do not overmix.
- Carefully pour in the hot water or hot coffee and mix until the batter is smooth and somewhat thin. This is normal for this type of cake.½ cup hot water or hot brewed coffee
- Pour the batter into the prepared cake pan. Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
- Let the cake cool in the pan for about 10-15 minutes before inverting it onto a wire rack to cool completely. Once fully cooled, you can trim off any domed top to create a flat surface for the mousse.
- In a small saucepan, combine the raspberries, 2 tablespoons of granulated sugar, and lemon juice. Cook over medium heat, stirring occasionally, until the raspberries break down and the mixture thickens into a syrupy sauce, about 5-7 minutes.1 cup fresh or frozen raspberries, 2 tablespoons granulated sugar, 1 tablespoon lemon juice
- For a smoother swirl, press the raspberry mixture through a fine-mesh sieve to remove the seeds. Let it cool completely.
- Place the finely chopped dark chocolate in a heatproof bowl.10 ounces good quality dark chocolate
- In a small saucepan, heat ½ cup of the heavy whipping cream over medium heat until it just begins to simmer around the edges. Do not boil.1 ½ cups heavy whipping cream
- Pour the hot cream over the chopped chocolate. Let it sit for 1-2 minutes to allow the chocolate to soften, then whisk gently until smooth and glossy. Stir in the vanilla extract and pinch of salt. Let this ganache cool slightly, but not set.1 ½ cups heavy whipping cream, 1 teaspoon vanilla extract, Pinch salt
- In a clean medium saucepan, whisk together the egg yolks and ¼ cup granulated sugar until pale and slightly thickened.2 large egg yolks, ¼ cup granulated sugar
- Gradually whisk the remaining 1 cup of heavy whipping cream into the egg yolk mixture.1 ½ cups heavy whipping cream
- Place the saucepan over medium-low heat and cook, stirring constantly with a wooden spoon or spatula, until the mixture thickens enough to coat the back of the spoon (around 170-175°F or 77-79°C). Do not let it boil, or the eggs will scramble.
- Pour the warm custard through a fine-mesh sieve into the bowl with the melted chocolate ganache. Whisk until fully combined and smooth.
- Cover the surface of the mousse with plastic wrap, pressing it directly onto the mousse to prevent a skin from forming. Refrigerate for at least 30 minutes, or until it's thickened to a pudding-like consistency but still spoonable.
- Place the cooled chocolate cake layer on your serving plate or cake stand. You can use the same pan you baked it in if you lined it with parchment, or gently lift it out.
- Spoon the chilled chocolate mousse evenly over the cooled cake layer, spreading it to the edges.
- Drizzle spoonfuls of the cooled raspberry sauce over the mousse. Use a toothpick or a skewer to gently swirl the raspberry sauce into the chocolate mousse, creating a marbled effect. Be careful not to over-swirl.
- Cover the cake loosely with plastic wrap (making sure not to smudge the top) and refrigerate for at least 4-6 hours, or preferably overnight, to allow the mousse to set completely.
- Once the mousse is set, remove the cake from the refrigerator. Decorate with fresh raspberries, chocolate shavings, or a dollop of whipped cream just before serving for maximum visual appeal.Fresh raspberries, Chocolate shavings, Whipped cream
Notes
Properly stored, the cake will stay fresh and delicious for 3 to 4 days. The components are best enjoyed within this timeframe to maintain optimal texture and flavor. The cake is meant to be served chilled and does not require reheating.
