Chop the chocolate and melt over a warm water bath. Mix butter, icing sugar, marzipan, vanillin sugar and orange peel. Sift flour over it and knead it. Halve the dough. Knead liquid chocolate and cocoa into one half. Form a roll (approx. 4 cm Ø) from each half of the dough and let it rest in the refrigerator overnight. Grind the candied orange peel finely.
Mix with sugar. Whisk the egg yolk and spread it on the dough rolls. Roll in the orange sugar. Cut into approx. 1/2 cm thick slices and place on 2 baking trays lined with baking paper. Press the pecan nut halves in lightly and sprinkle them with some remaining orange sugar. Bake the trays one after the other in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 10-12 minutes
Waiting time approx. 12 hours