Preheat oven to 350 degrees.

Form ground beef into 6 patties and place in a 13×9 casserole dish.

In a saucepan, combine cream of mushroom soup, water, gravy mix, and onion soup mix. Heat over medium low and stir until gravy is formed. Pour gravy over patties and top with sliced mushrooms. Bake at 350 degrees for 45 mins or until patties are cooked. Serve with hot mashed potatoes. Serves 6.