in a bowl, combine the eg white, onion, cracker crumbs, milk, horseradish, salt if desired and pepper. Add beef; mix well. Shape into four oval patties. Add beef; mix well. Shape into four oval patties
Fry in a skillet over medium heat for 10-12 minutes or until meat is no longer pink, turning once.
Remove and keep warm. Add gravy, mushrooms and water to skillet; heat for 3-5 minutes. Serve over patties and noodles if desired.