Combine flour, baking powder, sugar, and salt; stir well. Cut in lard and butter until mixture resembles coarse meal. Add egg yolk and milk to flour mixture, stirring until dry ingredients are moistened. Turn dough out onto a lightly floured surface; knead 10 to 12 times.
Roll dough to 1/4-inch thickness. Cut into 2-inch circles, and brush with 1 tablespoon melted butter. Make a crease across each circle, and fold one half over. Gently press edges to seal; brush tops with remaining butter. Place on greased baking sheets. Bake at 450° for 12 minutes or until lightly browned.