Combine first 4 ingredients in a medium bowl; cut in margarine with a pastry blender until mixture resembles coarse meal.
Combine buttermilk and egg, stirring until blended.
Add to flour mixture; stir just until dry ingredients are moistened.
Drop mixture by rounded tablespoonfuls, 2 inches apart, onto a baking sheet coated with cooking spray.
Bake at 350° for 10 to 12 minutes or until biscuits are lightly browned.