In a large skillet, heat a tablespoon of olive oil over medium heat. Add sliced onions and cook slowly for about 10 minutes until soft and golden brown.

Push onions to the side and add the ground beef. Break apart and brown thoroughly for 5-7 minutes.

Once the beef is cooked, stir in gluten-free soy sauce and seasonings. Cook for an additional 2 minutes.

Toast the buns until golden, then ladle the beef and onion mixture onto them, topping with cheese.

Place under the broiler for about 2 minutes until cheese is melted. Serve immediately.