In a bowl, beat the softened butter with sugar and egg yolks. Add flour with vanilla sugar and baking powder. Add ground poppy seeds, lemon zest, milk and mix thoroughly. Finally, lightly mix in the foam from the egg whites.
Preheat the oven to 360° F. Grease the Bundt cake form with butter and sprinkle with flour. Transfer the dough into the form and bake for about 45 minutes.
1. Mix all ingredients until you get a smooth, doughy texture. Wrap it with plastic wrap and leave it in a fridge for an hour (or overnight).
2. Roll out a thin layer of dough with the plastic wrap over the dough, preventing it from sticking to the rolling pin. Using a cookie cutter, cut the desired shapes and place them on a cookie sheet lined with a baking paper.
3. Preheat the oven at 360F and bake for about 12 mins or until done.