The butter cut into pieces and the flour is made of crumb. Add yolk, yogurt, lemon juice and mix a soft dough. Roll out a thin crust and cut into square pieces. In each square put 1 teaspoon jam flavored with cinnamon. The corners of the boxes are collected in the middle and pressed by a nut. Biscuits rank in greased with butter tray and bake in moderate oven. Once cool sprinkle with powdered sugar.