Preheat the oven to 375 degrees Fahrenheit. Place a cooling rack on a baking sheet.
Divide the ground beef into 8 even balls (approximately 1/4 pound each). Then form the balls into patties that are approximately 4 inches wide and 1 inch thick.
Place the patties on the prepared baking sheet. Season them with salt, pepper and garlic powder.
Bake for 20-25 minutes until the burgers reach an internal temperature of 160 degrees Fahrenheit.
Add a slice of cheese on top of each patty and bake for 1 minute to melt the cheese.
Add a lettuce leaf to the bottom bun of each bun.
Top each one with a patty from the pan.
Then top each patty with the sliced tomatoes, onion slices and top bun. Serve warm and enjoy!
Notes
Refrigerate any leftovers in an airtight container for up to 5 days.