1. knead together flour and butter pieces. Add sugar. Knead in egg yolk and salt. Shape dough into a ball and chill covered for approx. 30 min.
2. roll out dough in portions on lightly floured surface to 3-4 mm thickness. Use cookie cutters to cut out e.g. moons, fir trees and shooting stars (6-8 cm in size). Place on a baking tray lined with parchment paper. 3.
Stir egg white and powdered sugar. Brush the cookies with it. Bake at 225 °C on the middle shelf for 5 minutes. Cool.