Knead the flour with the baking powder, sugar, butter and the egg quickly to form a smooth dough. Halve the part. Knead the cocoa powder into one half, the orange peel and the orange liqueur into the other half.
Roll out the light dough into a 1/2 cm thick sheet. Shape the dark part into a 2.5 cm thick roll and wrap it in the light dough. Chill for about 30 minutes.
Now cut the rolling pin into 1/2 cm thick slices and place on a baking sheet lined with baking paper.
Bake in the preheated oven at 175 ° C for approx. 15 minutes.