Put marzipan into the bowl of a kitchen processor, add sugar, flour, orange zest, and egg whites, grind until smooth.
Spread the dough on baking sheets with a tablespoon at a distance of 5 cm from each other. Place the baking sheets in a preheated oven for 12 minutes. Remove the finished biscuits from the oven, transfer to a wire rack, let cool slightly.
Meanwhile, melt the chocolate in the microwave for about 30 seconds. Stir and microwave again for 30 seconds.
Pour chocolate over the biscuits and let them set.