1Make high protein bone broth caramelized onions by cooking diced onions until brown, deglazing with beef bone broth until liquid evaporates, adding a dash of soy sauce.
2Prepare the burger by mixing 6oz of 93% lean ground beef with salt, pepper, garlic, and 1 tbsp caramelized onions; form into a patty.
3Make a low-calorie burger sauce by combining light mayo, sugar-free ketchup, sweet relish, caramelized onions, salt, garlic, and pepper.
4Toast bread slices.
5Cook the burger patty until seared; add cheese slice and let it melt.
6Assemble the burger by spreading burger sauce on the toasted bread, adding the cooked patty with melted cheese and top with more caramelized onions.