Preheat the oven to 375°F. Line a large baking sheet with foil for easy cleanup and place an oven-safe wire rack on top. Lightly coat the rack with nonstick cooking spray.
Divide the ground beef into 8 equal portions (about ¼ pound each). Gently shape each portion into a patty about 4½ inches wide and ¾-inch thick, pressing a slight indentation into the center of each patty to help prevent shrinking.
Arrange the patties on the prepared wire rack, leaving a little space between each one.
Season both sides of the burgers with the salt, pepper, and garlic powder.
Bake for 20-25 minutes, or until the burgers reach an internal temperature of 160°F when checked with an instant-read thermometer.
If using cheese: Place a slice of cheese on each burger during the last 1 minute of baking, just until melted.
Place a lettuce leaf on the bottom half of each hamburger bun. Top with a burger, sliced tomato, sliced onion, and the top bun.
Serve immediately with your favorite burger toppings and sides.
Notes
Refrigerate leftover burgers in an airtight container for up to 5 days.
The cheese is optional but should be included in the ingredient list if you plan to use it.
Avoid overworking the beef when forming the patties to keep the burgers tender.
For extra flavor, lightly toast the hamburger buns before assembling the burgers.