Ingredients

For the sponge cake

90 g (½ cup + 1½ tbsp) All purpose flour

40 g (¼ cup + 1 tbsp) Unsweetened cocoa powder

1½ tsp Baking powder

150 g  (¾ cup) Sugar

3 Egg yolks

4 Egg whites

130 g (½ cup + 1 tbsp) Hot milk

70 g (⅔ stick) Butter

1 tbsp Coffee

For the white chocolate mousse

350 g (13 oz) Cold heavy cream. Add one third of the cream to your chocolate and the other two thirds at the end)

150 g (5.5 oz) White chocolate

1 tsp Vanilla extract

1 tbsp White rum (optional)

Method

For the sponge cake

In a clean glass or metal bowl beat the egg whites, with 1/2 tsp of lemon juice. Once foamy add the sugar one tablespoon at a time and whip egg whites until stiff peaks.

In another bowl mix the cocoa powder with the hot melted butter. Add the coffee, milk and the egg yolks. Add the dry ingredients.

Gently combine both mixtures together without deflating the egg whites.

Pour the batter in two greased and lined with parchment paper 8 inch pans and bake the cakes in a preheated oven at 160 °C (320 °F) for 20 - 25 minutes or until a toothpick comes out clean.

Cool completely.

For the white chocolate mousse

Cut the white chocolate into small pieces, and add a third of the heavy cream and microwave until the chocolate is fully melted.

Add the remaining cream, vanilla and rum if desidered.

Refrigerate until cold, then whip