Sift the flour and knead together with a teaspoon of butter, 5 tablespoons of very cold water and a pinch of salt to form a firm dough. Then roll out thinly and place the remaining butter (it must have the same temperature as the dough) in the middle, fold the dough over on both sides, roll out, turn over and roll out again in the opposite direction. Then let it rest for 20 minutes.
Repeat rolling out and letting rest three times. Chill the puff pastry for another 30 minutes before use.
Bring the milk to a boil. Stir the remaining ingredients until smooth and use the whisk to beat the boiling milk under them. Stir thickly in a water bath or on a low fire. Roll out the puff pastry thinly. Line the molds with it and add the cooled filling. Close the patties on top with a pastry lid. Bake in the preheated oven for about 20 minutes over high heat.