• 2 pounds freshly ground chuck
• Salt and freshly ground black pepper
• 8 slices white Cheddar, sliced 1/4-inch thick
• 8 slices yellow Cheddar, sliced 1/4-inch thick
• 8 perfect hamburger buns
• Horseradish Mustard, recipe follows
• 8 leaves romaine lettuce
• Grilled Vidalia Onions, recipe follows
• Dill pickles, sliced
• Ketchup
• Horseradish Mustard:
• 1/2 cup Dijon mustard
• 2 tablespoons prepared horseradish, drained
• Whisk mustard and horseradish together in a small bowl.
• Grilled Vidalia Onions:
• 2 Vidalia onions, sliced crosswise, 1/4-inch thick slices
• 2 tablespoons olive oil
• Salt and freshly ground black pepper
• Brush olive oil on both sides of the onions and season with salt and pepper. Grill the onion slices for 3 to 4 minutes on each side until golden brown.

1. Preheat grill or a cast iron skillet to high.
2. Divide the sirloin into 8 (4-ounce) burgers. Season on both sides with salt and pepper, to taste. Grill or cook in the skillet for 3 to 4 minutes on each side for medium-rare doneness. During last minutes of cooking add 2 slices of cheese to each burger, cover grill and let melt, approximately 1 minute. Place burger on bun and top with Horseradish Mustard, lettuce, Grilled Vidalia Onions, pickles and ketchup.
3. Horseradish Mustard:
4. 1/2 cup Dijon mustard
5. 2 tablespoons prepared horseradish, drained
6. Whisk mustard and horseradish together in a small bowl.
7. Grilled Vidalia Onions:
8. 2 Vidalia onions, sliced crosswise, 1/4-inch thick slices
9. 2 tablespoons olive oil
10. Salt and freshly ground black pepper
11. Brush olive oil on both sides of the onions and season with salt and pepper. Grill the onion slices for 3 to 4 minutes on each side until golden brown.

A classic and gorgeous burger by Bobby Flay.