Knead flour, sugar, vanilla sugar, 1 pinch of salt, butter in pieces and 1 egg first with the dough hooks of the hand mixer and then briefly with your hands to a smooth dough. Cover and chill for about 30 minutes.
Line baking trays with baking paper. Roll out the dough on some flour to a thickness of about 3 mm, cut out rabbits (5-8 cm long) and eggs (4.5 and 6 cm Ø). Put them on the baking trays. Use a punched spout (approx. 1⁄2 cm Ø) or a straw to pierce holes in the biscuits to hang them up.
Bake one after the other in a preheated oven (electric oven: 200 °C/circulating air: 175 °C/gas: see manufacturer) for about 8 minutes. Let them cool down.
Sift icing sugar for the icing. Whisk 1 egg white, lemon juice and icing sugar in a high mixing bowl with the whisk of the hand mixer until thick and creamy. If the icing is too firm, stir in some water.
Cut the cast in thirds. 1⁄3 Dye cast with red food colour pink and 1⁄3 Dye cast with yellow food colour. Fill each cast into a disposable piping bag and cut off a small corner at the bottom. Decorate cookies with it and sugar pearls.
Allow to dry.