2 tablespoons butter 1¼ cups mushrooms, thinly sliced 1 onion, thinly sliced 1 (10½ ounce) can condensed beef broth 1½ lbs ground beef ½ cup Panko bread crumbs 1 egg ¼ teaspoon black pepper 1 tablespoon all-purpose flour ¼ cup ketchup 2 teaspoons Worcestershire sauce ½ teaspoon mustard powder ⅓ cup water

Place butter in a frying pan with onions. Cook over medium heat about 5 minutes ensuring onions don't brown. Add mushrooms and cook until all liquid is absorbed.
In a bowl combine beef, ¼ cup of the broth, egg, pepper and Panko bread crumbs. Mix well and form 6 patties.
In another small bowl, combine remaining broth, flour, ketchup, Worcestershire sauce, mustard powder and water. Mix well.
Remove mushrooms/onions from the pan. Place beef patties in the pan and brown on each side (about 2 minutes). Place onions/mushrooms on top of patties and pour broth mixture over top. Cover and let simmer 20 minutes or until done. Serve with mashed potatoes!