Slice the onion and tomato.
Wash the lettuce thoroughly and set aside.
Season the ground beef with salt and pepper.
Shape the seasoned ground beef into patties.
Heat oil in a pan and cook the patties on both sides.
Cut the burger bun in half and lightly toast it.
Assemble the burger by layering the patty, onion, tomato, lettuce, and sauce on the bun.
Cover with the top bun to finish.