Sprinkle meat with salt and pepper. In a Dutch oven, brown meat in oil. Drain and remove from the heat. In a large saucepan, combine the cranberries, water and sugar. Cook and stir over medium heat until cranberries pop and liqued is slightly thickened, about 8 minutes. Remove from heat.
Add the broth and horseradish; pour over meat. Place cinnamon stick and cloves in a double thickness cheesecloth; bring up corners of cloth and tie with kitchen string to form a bag. Add to Dutch oven.
Cover and bake at 325 for 2 hours. Meanwhile, in a large saucepan, bring 6 cups water to a boil. Add pearl onions; boil for 3 minutes. Drain and rinse in cold water; peel and set aside. Add sweet potatoes to Dutch oven. Cover and cook 30-40 minutes more or until vegetables and meat are tender. Remove meat and vegetables; keep warm. Discard spice bag.
Cool pan juices for 10 minutes; transfer to a blender. Cover and process until smooth; return to pan. Combine cornstarch and cold water until smooth. Gradually whisk into pan juices. Bring to a boil; cook and stir for 1-2 minutes or until thickened. Serve with meat and vegetables.