Separate 4 eggs. Cream fat. Gradually add sugar, vanillin sugar, remaining eggs, egg yolk and rum and beat until foamy. Mix starch, baking powder and flour, stir in by the spoonful.
Beat the egg whites until stiff and fold in carefully. Line the bottom of a springform pan (20 cm Ø) with baking paper and spread a tablespoon of dough on top. Bake under the preheated grill for 1-2 minutes until golden brown.
Then again spread 1 tablespoon of dough on top and bake. In this way, gradually work the whole dough. Carefully remove the cake from the edge with a knife, turn it onto a cake rack and let it cool down.
Melt the dark chocolate coating in a hot water bath, let it cool down a bit and cover the cake with it. Let it set. Melt the white couverture as well. Spread on a cooled marble board and let it set in the fridge.
Use a spatula to scrape the rolls and garnish the cake with them. Dust with cocoa. Makes about 16 pieces.