Cheesy Broccoli Potato Soup

2 cups chopped carrots
1 small onion finely diced
2 cups broccoli florets
4 cups potatoes peeled and cubed
1 cup chopped celery

Boil all veggies but broccoli in 3 cups water for 10 min. Add the broccoli and boil for 10 more minutes. DO NOT DRAIN!

Sauce:
1/2 cup butter
3 Tbs. flour
2 cups milk
1 lb. velveeta cheese, cubed
1 teaspoon dry mustard
season with salt and pepper

In saucepan, melt margarine. Stir in flour. Add milk and cook on medium heat stirring constantly until thick. Add cheese and other ingredients. Stir until smooth. Add to undrained veggies and heat together, but do not boil.