Put 60 g flour, butter in flakes, 15 g sugar and 1 tablespoon cold water in a bowl. Knead with your hands to a smooth shortcrust pastry. Wrap the dough in foil and chill for about 30 minutes.
Separate eggs. Beat the egg whites, 3 tablespoons of water and salt with the whisks of the hand mixer until stiff. Add 100 g sugar and 1 packet of vanilla sugar. Stir in the egg yolks one after the other.
Mix 125 g flour and baking powder, sieve onto the egg mixture and fold in. Line the bottom of a springform pan (26 cm Ø) with baking paper. Fill in sponge cake mixture and smooth it down. In a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see
manufacturer) Bake for 20-25 minutes. Remove and let cool on a cake rack.
Roll out the short pastry on a floured work surface to a thickness of approx. 0.5 cm. Cut out stars of different sizes, place them on the ends of wooden skewers and press them on. Place stars with handles on a baking tray lined with baking paper and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see
manufacturer) bake for about 10 minutes. Take out and let cool down.
Mix 25 g sugar, 1 sachet of vanillin sugar and cream thickener. Whip 500 g cream until stiff, allowing the sugar mixture to trickle in. Fold in ground hazelnuts. Remove sponge cake from the tin, remove baking paper and cut the base twice horizontally.
Place the bottom cake layer on a cake plate and enclose with a cake ring. Spread half of the cream mixture on the lower cake base. Place the middle cake layer on top and spread with the rest of the cream. Put the lid on.
Chill the cake.
Mix 1 tbsp. icing sugar with approx. 1/2 tsp. water. Pour into a piping bag and decorate the cookie stars with it. Let the stars dry for about 30 minutes. Caramelise 1 tbsp. sugar in a small pan.
Add sliced hazelnut kernels and mix. Put them on a plate lined with baking paper and spread them out. Leave to cool.
In the meantime, dice the marzipan. Sieve 75 g icing sugar onto the work surface and knead with the marzipan. Roll out the marzipan between 2 layers of baking paper (approx. 35 cm Ø). Place the marzipan cover on the cake using the baking paper, paper
Press the marzipan cover lightly, cut off any excess marzipan.
Whip 100 g cream until stiff, fill into a piping bag with star-shaped spout. Decorate the top edge of the cake with cream, roughly break up the brittle and sprinkle on top. Decorate the cake with stars.