Separate eggs. Beat the egg whites until stiff, adding sugar, vanillin sugar and salt. Stir in egg yolk. Mix flour and baking powder, sieve onto the egg cream and fold in. Line a baking tray (32 x 39 cm) with baking paper and pour the mixture on top.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 10 minutes. Mix starch with a little water. Pour wild cranberries into a pot, bring to the boil, season with cinnamon and stir in the mixed starch, bring to the boil again.
Let it cool down. Turn the sponge cake base onto a tea towel, remove the baking paper. Place a second cloth on top and let it cool down. Halve the cake base crosswise, spread one half with the thickened wild cranberries.
Cover with the other half and chill. Mix 5 tablespoons of water with icing sugar. Fill 1-2 tablespoons of icing into a piping bag. Coat the cake with the rest and let it dry. Cut the marzipan in half, one half red, the other green.
Roll out marzipan, cut out with cookie cutters with different motifs (e.g. stars, fir trees and bells). Cut a small corner from the piping bag. Decorate the marzipan with the rest of the icing.
Cut the cake into 16 pieces and decorate with the marzipan motifs.