Make a smooth dough from the first 3 ingredients. Then divide the dough as follows: 1/3 and 2/3. The kl. The piece is kneaded with the tablespoon of cocoa powder. Then process like black and white pastries.
Shape the dough into a roll and place in the refrigerator.
When the roll has set, brush with egg yolk and roll in regular white sugar. Then cut into slices (0.4-0.5 cm thick) and place them on a baking sheet lined with baking paper.
Now bake the cookies at 180 ° C for 15-20 minutes. However, if they have a slight tan on the edge, watch out for them immediately.