Add onions and mushrooms; sauté over medium heat.
Sprinkle flour over onions and mushrooms. Add wine, soup and water; stir well. Add salt and pepper.
Return meat to pan. Bake covered at 325° for 1 1/2 hours.
Reduce heat to 275° and continue baking for 1 hour.
Refrigerate to cool meat before slicing.
Reheat and serve warm with French bread or roll.