In a medium bowl, combine ground beef with onion, cracker crumbs, egg white, milk, horseradish, salt and pepper. Shape into four 1/2" thick oval patties. Heat a large non-stick skillet at med until hot. Place patties in skillet; cook 7 - 8 min or until no longer pink and juices run clear, turning once. Remove from skillet; keep warm. Add gravy ingredients to same skillet. Cook over medium heat 3 - 4 min or until mushrooms are tender. Recipe By : Best Recipes 4/94 Posted to FOODWINE Digest 19 November 96 Date: Tue, 19 Nov 1996 18:34:47 -0600 From: Ellen Court