For the cookies, hard boil the eggs and pass the yolks through a sieve.
Mix with butter, half of the raw yolks, sugar and vanilla sugar until creamy. Knead in the flour. If needed, add a little milk to make the dough a little smoother.
Chill the dough for 1-2 hours. If the dough is too dry, knead in a little more milk.
Roll out 1/2 cm thick on a floured baking board, cut out with ramekins and place on a greased baking sheet.
Mix the remaining egg yolk with the condensed milk and brush the cookies with it. Preheat the oven to 175 °C and bake the cookie cutters for about 18 minutes.