Bobby Flay's Hamburgers with Double Cheddar Cheese and Grilled Vidalia Onions

Ingredients

Burgers:

• 2 pound(s) ground chuck
• Salt and freshly ground black pepper
• 8 slice(s) (1/4-inch thick) white Cheddar cheese
• 8 slice(s) (1/4-inch thick) yellow Cheddar cheese

Toppings:

• 2 tablespoon(s) olive oil
• 2 (1/4-inch thick) Vidalia onions, sliced crosswise
• 8 hamburger buns
• Horseradish mustard, for garnish
• 8 leaves romaine lettuce
• Pickles and ketchup (optional)

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Directions

1. Preheat grill to high. Shape the beef into eight 4-oz. burgers and season both sides with salt and pepper to taste. Grill for 3 to 4 minutes on each side for medium-rare, or to desired doneness. During last minute of cooking, add 2 slices of cheese (one of each kind) to each burger; cover grill and let the cheese melt, approximately 1 minute.
2. Meanwhile, brush olive oil on both sides of the onion slices and season with salt and pepper. Grill onions for 3 to 4 minutes on each side, until golden brown.
3. Place burgers on buns; top with horseradish mustard, lettuce, grilled onions, pickles, and ketchup, if you like.