Beat the butter, sugar and vanilla sugar. Add the egg yolks. Then add the flour and knead everything into a smooth dough.
Chill for approx. 1 hour - wrapped in foil.
Make small balls out of the dough and press them in a little in the middle (with the end of a wooden spoon or similar) - first place the balls on the baking sheet lined with baking paper (leave enough space).
Then fill the hollow with the jelly.
Bake in the fan oven at 140 ° until golden brown (please check, approx. 10 minutes). Dust with powdered sugar if necessary.