Finnish Tarts - cooking recipe

Ingredients

200 g butter
250 g flour
100 ml cold water
1 teaspoon vinegar
1 egg
6 tablespoons plum marmalade

Preparation

Mix all the ingredients expect from the egg and the marlalade. Make a dough and let it cool about 1 hour.
Roll the dough into a big circle and cut into small ones, by using a mug.
Place one teaspoon of marmalade at the middle of the circle and pinch the edges.
Beat the egg and shine the tarts.
Place on cookie sheets and bake at 470F for 30 minutes.