Separate eggs. Beat the egg whites with the whisks of the hand mixer until stiff. Add salt, 75 g sugar and vanillin sugar. Stir in egg yolks. Mix flour, starch and baking powder, sieve onto the egg mixture and fold in.
Spread the mixture evenly on a baking tray lined with baking paper (approx. 36 x 38 cm). Bake in a preheated oven (electric cooker: 220 °C/ convection oven: 190 °C/ gas: see manufacturer) for 8-10 minutes.
Take the sponge out of the oven and let it cool down.
Soak gelatine in cold water. Mix mascarpone, chestnut puree, 50 g sugar and cherry brandy. Squeeze the gelatine and melt it in a small pot. Stir in 5 tablespoons of mascarpone mixture, then stir into the rest of the mascarpone mixture, refrigerate.
Whip the cream with the whisks of the hand mixer until stiff. When the cream starts to gel, fold in the cream.
Turn the sponge onto the work surface, carefully peel off the baking paper. Halve the sponge cake. Place one half as a base on a cake plate, enclose with a square cake frame. Spread raspberry jam on the base.
Smooth the chestnut cream on top. Place the second sponge cake on top. Chill for at least 2 hours.
Roughly chop the milk chocolate and melt it over a warm water bath. Spread the slices with chocolate, chill for about 15 minutes. Chop dark and white chocolate separately and melt over a warm water bath.
Pour into a piping bag with a small perforated nozzle. Cut into about 9 squares. Decorate each square with chocolate lentils and the chocolate varieties as reindeer face. Dust with some cocoa powder if necessary.