South Beach Classic Burger

Ingredients

• 1 1/2 lbs. lean ground beef
• 1/4 tsp salt
• 1/2 tsp freshly ground black pepper
• 2 ozs.low-fat Swiss cheese slices
• 4 tsp Dijon mustard
• 4 green leaf lettuce leaves
• 1 med. tomato,sliced
• 1 small red onion,thinly sliced