1. Beat egg whites at high speed until foamy.
2. Add milk and margarine; beat at medium speed until well blended.
3. Gradually add bread flour, whole wheat flour and salt, beating until mixture is smooth.
4. Coat muffin pans with cooking spray.
5. Heat at 450 degrees for 2-3 minutes or until hot. Remove pans from oven.
6. Pour 1 tablespoon batter into each cup; sprinkle each with 1 teaspoon cheese.
7. Fill cups three-fourths full with remaining batter.
8. Bake at 375 degrees for 45 minutes.
9. Cut a small slit in top of each turnover and bake an additional 5 minutes.
10. Serve immediately.