Heat oven to 375°.
Mix flour, cornmeal, baking powder, salt and sugar.
Mix egg and sour cream; stir into flour mixture.
Place on lightly floured surface and roll 1/4 inch thick.
Cut into 3-inch rounds; brush with margarine and fold in half.
Place on ungreased cookie sheet.
Bake 12 to 15 minutes or until rolls are golden brown.