Separate 1 egg. Mix butter, sugar, egg and egg yolk. Mix flour, baking powder and salt and knead into the egg-fat mixture. Wrap the dough in foil and chill for at least 1 hour. Roll out the dough and cut out cookies with 2 cutters (8.5 + 5 cm). Spread the cookies on 2 baking trays lined with baking paper.
Bake the trays one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes. Beat the egg whites and icing sugar with the whisks of the hand mixer. Halve the icing. Colour one half lilac. Fill the icing into the piping bags and decorate cooled cookies with icing and sugar pearls
waiting time approx. 1 1/2 hours