Beat the butter, sugar and eggs until frothy. Add salt and vanilla sugar. Finally, sieve the flour over it and knead everything quickly. Chill the dough. (Around 1 hour)
Roll out the dough thinly on a surface sprinkled with flour and cut out the cookies. Bake at 180 ° for about 10 minutes.
Make a icing from the powdered sugar and a little lemon juice. Only use enough juice that the glaze is thick and spreadable. To make it look nicer, I add some food coloring to the glaze.
Cover the cookies with it and decorate with sprinkles.