*You might need more or less, depending on how meaty the ribs are.
Preheat oven to 350°.
Trim excess fat from beef short ribs. Place ribs in a 13-9-inch baking pan or large shallow roasting pan. Sprinkle with salt and pepper. Bake uncovered for 2 hours then drain off excess fat. Add carrots, potatoes, green beans, and onions. In a bowl, combine the broth with horseradish and mustard; pour over meat and vegetables. Cover with foil and bake for 1 to 1 1/2 hours longer, or until tender. Arrange the beef short ribs and vegetables on a serving platter and keep warm. Measure pan drippings and add a little water or broth, if necessary, to make 2 cups. Return to baking pan or pour into a saucepan and place over medium heat.
In a cup or small bowl, mix cornstarch with cold water. Stir into the pan drippings and bring to a boil, stirring constantly. Boil for 1 minute. Serve the pan gravy with the short ribs and vegetables.
Calories per serving: 640
Fat per serving: 22.1g