Preheat oven to 350 degrees F (175 degrees C). Line baking sheets with parchment paper.
Combine the flour, baking powder, butter or margarine, sugar, sour cream and eggs. Knead until dough is smooth.
Sprinkle a work surface generously with confectioners' sugar. Roll dough out over the confectioners' sugar to 1/4 inch thick, adding more as needed. Cut out into 3 inch squares and fill with nut, poppyseed or prune filling.
Bake at 350 degrees F (175 degrees C) for 15 minutes. Enjoy!