Cream butter, icing sugar and vanillin sugar with the whisk of the hand mixer. Stir in the egg. Mix cocoa and flour and knead in. Work into a smooth dough with your hands on a floured work surface. Wrap the dough in foil and chill for about 1 hour.
Roll out dough on a floured work surface 3-4 mm thin and cut out approx. 55 crescents (approx. 6 cm long). Knead dough remains and roll out again. Put the biscuits on 2 baking trays lined with baking paper. Bake one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 8 minutes. Remove the biscuits from the oven and let them cool down on a cake rack. Coarsely chop the white chocolate coating. Melt the couverture and coconut oil in a bowl over a warm water bath. Brush the biscuit surface with a brush and refrigerate for about 1 hour until the chocolate coating is firm. Chop the milk chocolate coating and melt over a warm water bath.
Remove the biscuits from the oven and let them cool down on a cake rack. Coarsely chop the white chocolate coating. Melt the couverture and coconut oil in a bowl over a warm water bath. Brush the biscuit surface with a brush and refrigerate for about 1 hour until the chocolate coating is firm. Chop the milk chocolate coating and melt over a warm water bath. Decorate the biscuit surface and put the biscuits in a cool place for approx. 1 hour until the chocolate is firm
waiting time approx. 3 hours