In a bowl add milk, sugar, vanilla sugar and room temperature butter cut into pieces.

Heat the milk and sugar mass in a saucepan. Once the butter has melted, allow the milk to boil and simmer for a few minutes.

Sift the flour. Remove the milk mass from the heat. Scatter the flour in several portions and mix the mass vigorously to prevent the flour from popping into tubers. Mix until the dough is smooth, thick and shiny.

Let the dough cool. Continue to cook the cookie dough just to keep it warm.

Beat the eggs individually and pour them into the dough gradually, whipping it with a whisk. It is important to make sure that the dough does not become too liquid (it is possible that the egg whip may remain).

Place the dough in a pastry bag with a slightly trimmed tip. Cover the baking sheet with baking paper. Make dough cookies of the size wanted. Anoint them with egg whip.

Bake the biscuits in a 180 degree oven for about 45 minutes (on the average oven shelf or just below).