Break the eggs into a bowl and add the sugar. Stir in vanilla sugar and mix immediately with a whisk.
In a second bowl, mix the flour and butter, softened with your hands, to obtain a sandy dough.
Stir in the sugar-egg mixture and baking powder, then work the dough until smooth. Film it and let it rest for 1 hour in a cool place.
Knead the dough and roll out to a thickness of about 4 mm. Cut out shapes with cookie cutters and place on a baking sheet covered with parchment paper.
Brush them with egg yolk to brown them, then put them in the oven at 180°C for 10 to 15 minutes.