In a large bowl, combine the ground beef, egg, almond flour, salt, pepper, garlic powder, and onion powder.
Mix well and form the mixture into 4 patties.
Heat a large skillet over medium heat and cook the patties for 4-5 minutes on each side, or until they are fully cooked.
Place a slice of cheddar cheese on top of each patty during the last minute of cooking to allow it to melt.
Toast the hamburger buns in the oven or on the stovetop.
Assemble the burgers by placing a lettuce leaf, a tomato slice, and a patty on each bun.
Serve and enjoy your delicious keto burger!