Cut beef into 1 inch cubes. Sprinkle with tenderizer. In a Dutch Oven, saute garlic and onions in butter slowly until onions are clear or slightly browned. Remove onions and brown meat slowly in the drippings. Add beef gravy, salt, pepper and onions to pan. Simmer over low heat 2-4 hours or until meat is tender. Stir in sour cream the last 15 minutes of cooking time. Serve over rice or egg noodles.
