1. Sprinkle beef with salt and pepper; brown beef in batches in hot oil in a Dutch oven over medium-high heat. Remove beef from pan; set aside. Saute celery and onion for 5 minutes. Add the garlic; saute 30 seconds. Return beef to pan; add broth (I used beef broth) and 1 3/4 cups water. Bring to a boil and then simmer for about an hour.
2. Add the Yukon potatoes; cook, covered, 10 minutes, add sweet potatoes; cook 20 minutes or until beef ad potatoes are tender.
3. Combine flour and remaining 1/4 cup water, stirring until smooth. Gradually stir into meat mixture; cook 1 minute or until cheese melts. Sprinkle each serving with freshly ground pepper just before serving.