PREPARATION:

1. Heat 1 tablespoon oil in large nonstick skillet. Add bell pepper and onion. Cook and stir over high heat 3 minutes or until tender. Sprinkle with 1/4 teaspoon salt, 1/4 teaspoon black pepper and red pepper flakes, if desired. Remove from skillet; set aside.
2. Heat remaining tablespoon oil in skillet. Sprinkle steaks with remaining 1/4 teaspoon salt and 1/4 teaspoon black pepper.
3. Add steaks to skillet. Cook 2 minutes over high heat. Turn steaks; cook 1 minute or until desired degree of doneness. Cover each steak with 1 slice cheese. Heat 1 minute or until cheese melts.
4. Divide bell pepper mixture among 4 plates. Top each serving with 1 steak.