Combine flour, baking powder, salt, and 1/4 teaspoon pepper in a bowl; cut in margarine with a pastry blender or 2 knives until mixture resembles coarse meal. Add cheese; toss well. Add milk, stirring just until dry ingredients are moistened.
Turn dough out onto a well-floured surface, and knead 4 or 5 times. Roll dough to 1/2-inch thickness; cut with a 2-inch decorative cookie cutter. Place biscuits 1 inch apart on baking sheets coated with cooking spray, and brush with egg white; sprinkle with remaining pepper. Bake at 425° for 15 minutes or until lightly browned.