Combine ground beef, onions, rice, black pepper and egg; divide into six equal portions. Shape each into a 1 inch thick patty. Coat a skillet with cooking oil and cook patties for 5 minutes on each side. Remove from skillet; keep warm.
Add mushrooms to the skillet and cook for three minutes. Add Worcestershire sauce, salt and beef broth; cook for another ten minutes.
Return patties to the skillet, cover and simmer for 15 minutes. Remove the patties to a platter; keep warm. Combine water and cornstarch; add to broth mixture, stirring well. Bring to a boil then cook ONE minute more. Serve over patties.
