In a large skillet, heat a tablespoon of oil over medium heat. Add thinly sliced onions, stirring occasionally for about 15-20 minutes, until they become soft and golden brown.

In the same skillet, push the caramelized onions to one side and add a pound of lean ground beef to the empty space. Cook over medium-high heat for about 5-7 minutes, breaking the beef into smaller pieces until browned and fully cooked.

Add the caramelized onions back to the skillet with the cooked ground beef. Pour in a tablespoon of gluten-free soy sauce, then mix everything together thoroughly. Cook for an additional 3-4 minutes.

Sprinkle your chosen melting cheese over the beef and onion mixture. Cover with a lid and cook for 2-3 minutes on low heat, until the cheese is completely melted.

Slice and toast your soft buns. Spoon the beef and onion mixture onto each bun, allowing the melted cheese to cascade over the edges.