In a large bowl,combine the first 5 ingredients. Cut in the margarine until the mixture resembles coarse crumbs.Stir int the milk and sour cream to make a soft dough. On a lightly floured surface,knead the dough 2 minutes. Press to a 3/4-inch thickness. With a 2 1/2 inch round cookie cutter, cut into 12 biscuits.
Spray a cookie sheet with nonstick cooking spray. place the biscuits on the cookie sheet 1 inch apart.
bake for 10 to 12 minutes, or until the tops are golden brown. Cool on a wire rack.