You can find prepared horseradish in glass jars in the condiment section of your supermarket.
Skip the gravy and serve with more horseradish or a fruit chutney.
To carve the roast, place on carving board or serving platter so the meat grain runs parallel to carving board. Holding meat in place with meat fork, cut meat across grain into 1/4-inch slices.
For Cream Gravy Pot Roast, substitute 1 can (10.5 ounces) condensed beef broth for the 1 cup water. For the gravy in step 4, add enough half-and-half or milk, instead of water, to the broth (from the roast) to measure 2 cups. Substitute 1/2 cup half-and-half or milk for the 1/2 cup cold water.
For Garlic-Herb Pot Roast, decrease pepper to 1/2 teaspoon and omit horseradish. After browning beef in step 1, sprinkle with 1 tablespoon chopped fresh or 1 teaspoon dried marjoram leaves, 1 tablespoon chopped fresh or 1 teaspoon dried thyme leaves, 2 teaspoons chopped fresh or 1/2 teaspoon dried oregano leaves and 4 cloves garlic, finely chopped. Substitute 1 can (10.5 ounces) condensed beef broth for the 1 cup water.