Halve the shortcrust pastry. Knead half a dough, 20 g cocoa, orange peel and cardamom. Work the dark dough into 4 rolls of 15 cm length each, put them in the freezer. In the meantime, roll out the light-coloured dough on a lightly floured work surface to form 2 dough sheets of 15 x 16 cm. Whisk egg yolk and cream. Brush the dough plates with it.
Place 1 roll on each 15 cm edge and roll up each side towards the middle, freeze again briefly. Spread the outside of the dough with whisked egg yolk and sprinkle with sugar. Cut into thin slices and place on 2 baking trays lined with baking paper. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 10-12 minutes, let cool down. Chop the chocolate and melt over a warm water bath. Dip the biscuits delicately into the chocolate, allow to dry and dust with cocoa