Mix the butter, sugar, vanilla sugar and egg yolks until frothy. Gradually add the flour and knead into a dough.
Shape the dough into even balls with a diameter of approx. 2 cm. Press an indentation in the middle of each. Brush the edge with the egg yolk and dip in the almond powdered sugar mixture (mix the powdered sugar with the ground almonds for the mixture).
Then fill the recess with a jam of your choice, chill the biscuits for about 30 minutes and then bake them in a preheated oven at 180 degrees for about 10-12 minutes.
I also like to fill the recess with nut nougat cream, it also tastes really delicious.