DirectionsBoil carrots, celery, and green onions in 2 cups of water for 5 minutes. Sauté white onion in butter. Add flour and blend well. Boil milk and chicken broth. Stir briskly into white onion mixture with a wire whisk. Add cheese, salt, pepper and cayenne. Stir in mustard and the boiled vegetables including the water in which they were cooked. Bring to a boil and serve immediately.