2 pounds beef tenderloin or
  chuck roast
1 cup water
10.5 ounces cream of celery soup
1 packet brown gravy
1 packet onion soup mix

Preheat oven to 300 degrees. Cube meat and add to prepared 9-by-13 baking dish. In large bowl, whisk together water, cream of celery, brown gravy packet and onion soup mix packet. Pour mixture over meat and stir to coat. Cover pan with tin foil and bake for three hours. Serve over mashed potatoes.