Mix marzipan with egg yolk, sieved icing sugar and fat with the whisks of the hand mixer until smooth. Add orange zest and flour bit by bit. Pour into a piping bag with a smooth perforated spout and squirt small heaps onto a baking tray lined with baking paper.
The biscuits must be far apart, as they melt wide. Bake in the preheated oven (electric: 175 °C/ gas: level 2) for 8-10 minutes until light and remove from the tray immediately. Melt the couverture and decorate the cookies with thread-thin stripes irregularly.
Results in about 30 cookies.