Dice marzipan. Mix egg, egg white, 75 g sugar and marzipan carefully with the whisk of the hand mixer (no lumps should be left). Pour into a piping bag with a small star-shaped spout.
Line 2 baking trays with baking paper. Spray 10 clefs of about 10 cm length. Spray two 5 cm long strips of remaining dough close together. Spray 2 strips of about 7 cm each side by side.
Bake the trays one after the other in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: stage 2) for 10-12 minutes. Puree 2 tablespoons of sugar in the universal food processor. Add food colouring as desired.
Dust the biscuits with the sugar.