Lighter Salisbury Steak

Mix the beef, egg, crushed crackers, ½ cup chopped onion, Worcestershire, Dijon, and half of the no-sugar ketchup. Season the mixture with garlic powder, onion powder, salt, and pepper to taste. Shape the mixture into four patties and brown both sides in a pan. Remove the patties from the pan. In the same pan, make the gravy by adding butter, 1 cup mushrooms, remaining onions (if any were reserved, though the instruction says 'onions' without specifying which half was used for gravy), flour, 1 cup water or broth, beef base, balsamic vinegar, and the remaining half of the ketchup. Return the browned Salisbury steaks to the pan with the gravy and simmer until the gravy is thick, rich, and glossy.