Cut plums into strips. Beat eggs, sugar and vanilla sugar with the whisk of the hand mixer until foamy. Add Baileys and oil one after the other while stirring. Mix flour and baking powder, sieve onto the foam and stir in. Spread 2/3 of the dough on a greased baking tray sprinkled with breadcrumbs. Sift the cocoa onto the remaining dough and stir in.
Pour in wide strips onto the light-coloured dough. Put plums on the dark dough strips. Bake in the preheated oven (electric: 200 °C / gas: level 3 for about 20 minutes. Let the cake cool down and cut into 16-20 pieces. Arrange on a plate and serve dusted with icing sugar. Results in approx. 16 pieces