Sponge:

• Melt the butter over a low heat and leave to cool. Combine the flour with the cocoa powder.
• Whip the eggs well with a pinch of salt and the sugar until they triple in volume. Add the melted butter and mix for another 10 seconds. Turn off the mixer. Gently fold in the dry ingredients using upward movements.
• Preheat the oven to 180 °C (360 °F) . Line a 20/30 cm (8x12 inches) baking tray with parchment paper. Pour the mixture into the tray and level it. Bake for 25 minutes or until it passes the toothpick test. Transfer to a cooling rack.
• When completely cooled, cut in half horizontally. Put one piece of the cake back into the baking tray. Lightly coat it with cocoa syrup. Cover the other piece of the cake with a clean towel to keep it moist.

Chocolate cream:

• Hydrate the gelatin sheets in cold water. Place the milk over medium heat together with 100 ml (1/2 cup) of the whipping cream. When almost boiling, turn off the heat. Add the chocolate, broken in pieces, and leave to rest for two minutes. Add the coffee and the vanilla extract and stir well, then add the drained gelatin and stir again until fully dissolved. Refrigerate for an hour.
• Whip the rest of the whipping cream with the vanilla sugar until it turns into a firm foam. Fold the whipped cream into the cooled chocolate cream with upward motions. Spread the chocolate cream on top of the cake. Level it off nicely and place the second chocolate cake on top. Gently drizzle the chocolate syrup over the top. The cake is not quite dry so it doesn't need that much syrup, just enough to make cutting it easier. Cover the cake with cling film and refrigerate.

Caramel cream:

• Hydrate the gelatin in cold water.  Roast the hazelnuts in the oven for 10 minutes at 180 °C (360 °F). Place on a chopping board to cool then chop them coarsely.
• Bring the milk to almost boiling point. Add the gelatin and stir well. Gradually add the dulce de leche and stir gently until you get a smooth consistency. Incorporate the hazlenuts. Pour the caramel cream over the chocolate cake, smooth it out, and refrigerate again.

Fruit cream:

• Hydrate the gelatin in cold water. Place the fruit, sugar and water over a medium heat. Leave to boil for 10 minutes until soft. Strain the fruit, keeping the liquid. Add the drained gelatin to the liquid and stir well. Refrigerate until it reaches the desired consistency.
• Whip the whipping cream along with the vanilla sugar and then add it to the fruit cream using upward movements. Spread the berry mousse over the caramel cream and level it with a spatula. Cover with cling film and refrigerate again.

Raspberry jelly:

• Hydrate the gelatin in cold water. Bring the raspberries, sugar, and water to a boil. Let it boil for 6 minutes then turn off the heat. Pass the raspberries through a fine sieve and add the gelatin to the resulting liquid. Stir well. Leave the cream aside for half an hour until it gets a light consistency. Pour the cream over the cake and level it very slowly with a spatula.
• Refrigerate overnight.

Enjoy!