Marble Cake

Preheat the oven to 180°C (350°F) and grease a round cake tin with butter.

Prepare the sponge mix according to package instructions with the 2 eggs, then fold in the orange juice and zest until evenly combined.

Divide the batter in half—set one portion aside and fold the cocoa powder into the remaining half until fully incorporated for the dark layer.

Alternate spoonfuls of the plain and cocoa batters into the prepared tin, starting with the plain batter and rotating colors for a marbled effect.

Bake in the preheated oven for 35 minutes until a skewer inserted into the center comes out clean.

Remove the cake from the oven and allow it to cool in the tin for 10 minutes, then turn out onto a wire rack to cool completely.

Melt the bitter chocolate and butter together over a low heat or in a double boiler, stirring until smooth and glossy.

Whip the thick cream until soft peaks form, then gently fold it into the warm chocolate-butter mixture until well combined.

Once the cake is completely cool, spread or drizzle the chocolate cream topping over the surface, allowing it to set slightly before serving.