Mix the flour with baking powder and sift into a mixing bowl. Add sugar, vanilla sugar, rum flavoring, rum and butter and knead into a dough. Knead half of the dough with cocoa. Knead the dough briefly so that they do not mix. Shape into a 3 cm thick roll and freeze for 1 hour.
Cut the rolling pin into approx. 6 mm thick slices and place them on a baking sheet lined with baking paper. Push the tray into the middle of the preheated pipe.