Start by adding the all-purpose flour and cold margarine to a bowl, adjust the salt, and mix all the ingredients well until you get a dough.
Now, place the dough in mini pie molds, add your preferred filling, and then cover with another layer of dough.
Next, brush a beaten egg yolk over the dough, place the molds on a baking sheet, and bake in a preheated oven (180ºC or 350ºF).
Finally, bake for about 40 minutes (or until golden brown), remove from the oven, take out of the molds, and it’s ready to serve.