Classic Ground Beef burgers with a classic topping of grilled onions. Old school is making a comeback.
Lightly shape Ground Beef into four 3/4-inch thick patties. Brush onion slices with cooking spray.
Place patties and onion slices on grid over medium, ash-covered coals. Grill, covered, 11 to 15 minutes (over medium heat on preheated gas grill, 13 to 14 minutes) until instant-read thermometer inserted horizontally into center registers 160°F, turning occasionally. Grill onions, 10 to 12 minutes or until tender, brushing with cooking spray and turning occasionally.
Cooking times are for fresh or thoroughly thawed ground beef. Ground beef should be cooked to an internal temperature of 160°F. Color is not a reliable indicator of ground beef doneness.
To toast buns, place cut sides down around outer edge of grid. Grill until lightly toasted.
Season burgers and onions with salt and pepper, as desired.
Line bottom of each bun with lettuce. Place burgers on top of lettuce. Top with tomatoes and grilled onions. Close bun.