Sugar Cookies

INGREDIENTS:
1/2 cup butter
1 cup sugar
1 tablespoon milk
1/2 teaspoon vanilla or other flavoring
2 eggs
2 teaspoons baking powder
1/4 teaspoon salt
2 cups flour
PREPARATION:
Cream butter with sugar; add beaten egg yolks, flour, baking powder, salt, milk, and stiffly beaten egg whites. Add enough more flour to make of consistency to roll. Cut off small pieces of the dough; roll on floured surface, sprinkle with granulated sugar, cut out with cookie cutter and bake on greased cookie sheets at 350° for about 10 minutes.