1Boil 2 cups of water in a pot. Add the broccoli, carrots, and celery. Cook 3-5 minutes, then drain and set aside.
2In the same pot, saute the onion in butter until tender. Whisk in flour to form a paste. Gradually add in the milk and broth, whisking to combine. Bring to a boil, stirring for 1 minute. Add the vegetables and remaining ingredients. Reduce heat and simmer, covered, 20-30 minutes until the vegetables are tender.
3Serve the soup with shredded cheddar cheese and crackers or bread.