Separate eggs. Beat the egg whites and 1 1/2 tablespoons of water until stiff, adding 50 g sugar. Stir in egg yolks. Mix flour, starch and baking powder and fold into the mixture. Line half of the baking tray with baking parchment, fold a bar of aluminium foil and place in front of the baking parchment. Spread the mixture evenly on the laid out half.
Bake the sponge cake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 8 minutes. Remove and let cool off. In the meantime, whip cream until stiff and allow vanilla sugar, 30 g sugar and cream firming agent to trickle in and carefully fold in the ground hazelnuts. Put the nut cream in a cool place. Remove the sponge cake from the baking paper and place on a large board. Cover with a baking frame if necessary. Spread the cream mixture on top and smooth it down. Chill the cake for 1 hour. Coarsely chop the milk chocolate coating and melt it with coconut oil over a warm water bath and let it cool slightly. Spread the couverture, except for 1 tablespoon, on the cake, smooth it down with a pallet and refrigerate for 1 hour. Pull the hazelnuts through the rest of the couverture and place them on a small plate lined with baking paper and chill.
Cover with a baking frame if necessary. Spread the cream mixture on top and smooth it down. Chill the cake for 1 hour. Coarsely chop the milk chocolate coating and melt it with coconut oil over a warm water bath and let it cool slightly. Spread the couverture, except for 1 tablespoon, on the cake, smooth it down with a pallet and refrigerate for 1 hour. Pull the hazelnuts through the rest of the couverture and place them on a small plate lined with baking paper and chill. Chop the dark and white couverture and melt each over a warm water bath. Place alternating strips on a marble board, spread thinly and chill. When the couverture is just firm, use a spatula to remove rolls. Place in a cold place. Take the cake out of the fridge, cut it into pieces and decorate with the coated hazelnuts and chocolate rolls
Chop the dark and white couverture and melt each over a warm water bath. Place alternating strips on a marble board, spread thinly and chill. When the couverture is just firm, use a spatula to remove rolls. Place in a cold place. Take the cake out of the fridge, cut it into pieces and decorate with the coated hazelnuts and chocolate rolls
2 hours waiting time