1. Heat a grill pan over medium high heat. Coat pan with cooking spray. 2. Sprinkle steak evenly with salt and pepper. Add steak to pan; cook 6 minutes on each side or until desired degree of doneness. Remove steak from pan; let stand 10 minutes. 3. Add onion to pan; cook 3 minutes on each side or until lightly browned. 4. Remove from pan; cool. 5. Combine ketchup and next 4 ingredients in a large microwave safe bowl, stirring well. Microwave on high 1 minute or until thoroughly heated. 6. Cut steak diagonally across grain into thin slices. 7. Add steak to ketchup mixture; toss to coat. Divide steak mixture evenly among bottom halves of rolls; top each serving with one onion slice. 8. Place top half of roll on each sandwich.
