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For the Sponge (2 layers):
5 egg whites
A pinch of salt
100g sugar
70g flour
70g roasted and ground almonds
20g cocoa powder
5g baking powder
For the Syrup:
3 teaspoons instant coffee (Nescafé)
4 teaspoons sugar
Approx. 300 ml cold milk (3.5% fat)
For Cream 1:
5 egg yolks
1 sachet vanilla sugar
100g sugar
70g cornstarch
700ml milk (3.5% fat)
200g soft butter (82% fat)
For Cream 2:
400ml heavy cream (36% fat)
60g powdered sugar
200g mascarpone
1 tablespoon cocoa powder
For the Glaze:
100g dark chocolate (54.5% cocoa, Callebaut)
100ml heavy cream (36% fat)
Sponge:
Beat the egg whites with a pinch of salt until soft peaks form. Gradually add sugar and continue beating until soft peaks are formed (a lower height sponge is preferred).
Sift in the flour, cocoa powder, and baking powder. Gently fold to combine. Finally, add the ground almonds and mix well.
Line a 24×24 cm (9.5-inch) square pan with parchment paper. Pour the batter into the pan, leveling it out.
Bake in a preheated oven at 180°C (350°F) for about 30 minutes or until a toothpick comes out clean.
Once baked, remove from the oven, take the sponge out of the pan, and let it cool. Repeat the same steps for the second layer of sponge, using defrosted egg whites if needed.
Cream 1 (Custard Cream):
Prepare this cream first to allow it to cool properly.
In a bowl, whisk together egg yolks, vanilla sugar, sugar, and cornstarch. Gradually add milk while stirring.
Place the bowl over a double boiler and whisk continuously until the mixture thickens and begins to bubble.
Remove from heat, cover with plastic wrap directly on the cream’s surface, and let it cool.
Beat the soft butter for 2-3 minutes, then gradually add spoonfuls of the cooled custard and mix until fully incorporated.
Cream 2 (Mascarpone Cream):
In a bowl, combine the chilled heavy cream, mascarpone, and powdered sugar.
Beat on low speed to start, then increase to medium speed. Add cocoa powder and continue beating until a smooth, fluffy cream forms.
Syrup:
Mix the instant coffee with sugar and dilute it with cold milk.
Glaze:
Place the chocolate and heavy cream in a heatproof bowl over a double boiler. Stir until the chocolate melts and becomes fluid.
Assembly:
Line the pan in which you baked the sponge with plastic wrap, and line the sides with acetate strips.
Place the first layer of sponge in the pan. Use a fork to poke holes in the sponge to help the syrup soak in, as the sponge is dense.
Pour half of the syrup over the sponge, letting it absorb for 2-3 minutes.
Spread the first cream layer evenly over the sponge.
Place the second soaked sponge layer on top and spread the second cream layer over it.
Pour the chocolate glaze over the second cream layer and smooth it out.
Refrigerate the cake overnight. The next day, cut it into portions using a serrated knife dipped in hot water.