Place roast in roasting pan. Make a paste with dry onion soup and ketchup. Smooth it over the roast and add 1/2 cup water around the roast. Bake at 250 degrees for 4 to 5 hours adding water as necessary. The last hour place in carrots and potatoes and continue to bake until veggies are tender. Baking time will depend on the size of the roast.