2
In 5-quart Dutch oven or roasting pan, heat oil over medium-high heat. Add beef roast; cook 4 to 5 minutes on each side or until browned. Remove from heat.
3
Meanwhile, in small bowl, combine mustard, flour, horseradish, 1 1/2 teaspoons salt and the pepper; mix well. Spread on both sides of browned roast. Add water. Cover; bake 30 minutes.
4
Add potatoes, carrots and onion to pot; sprinkle with remaining 1/2 teaspoon salt. Cover; bake 1 to 1 1/4 hours or until beef and vegetables are tender. Arrange beef and vegetables on serving platter.
5
With wire whisk, whisk remaining pan juice gravy until thickened and no large lumps remain. Add additional flour, if needed, for desired thickness.