Slice two large onions into thin strips. Heat a large skillet over medium heat and add a bit of oil. Add the onions and a pinch of salt, stirring occasionally. Caramelize for about 15-20 minutes until golden brown.

Add one pound of lean ground beef to the skillet. Break it apart and cook for about 8-10 minutes, stirring frequently, until browned and no longer pink.

Incorporate gluten-free soy sauce along with salt and pepper. Stir well and cook for an additional 2-3 minutes to meld the flavors.

Prepare your gluten-free buns by toasting them lightly. Spoon the beef mixture onto the bottom half of each bun and top with cheese.

Place the assembled sandwiches under the broiler for 1-2 minutes or until the cheese is melted and bubbly.

Remove sandwiches from the broiler. Serve warm with sides like oven-baked fries or a crisp green salad.