Combine soft butter with sugar, baking powder, vanilla, salt and egg.
Whisk and add milk.
Mix everything. Add salt and flour.
Knead a soft and elastic dough that does not stick to your hands.
Roll out the dough to a thickness of 5-7 mm., And cut out the figures using molds or a regular glass.
Transfer the blanks to a baking sheet covered with parchment (I have a silicone mat). Brush the top with whipped yolk. Bake in the oven at 200 degrees for about 15 minutes.