Zupas Wisconsin Cauliflower Soup

1 medium onion, chopped
3 T butter
2 pounds cauliflower chopped into 1 inch pieces (can use frozen)
1/4 C flour or corn starch
2 C half and half
1 1/2 c water
1 14.5 ounce can chicken broth
1 1/2 C sharp cheddar cheese, shredded
1/2 C pepper jack cheese, shredded
1/2 t salt
1 t dijon mustard

Optional Toppings:
green onions
bacon bits
additional cheese, shredded

1. In a large pot, melt 3 T butter and cook the chopped onion  until translucent and golden brown. Whisk in the flour or corn starch.  Gradually stir in half and half, water, and chicken broth.

2. Add the chopped cauliflower and heat to boiling.  Reduce heat to medium low and allow the cauliflower to cook until tender, about 15 minutes.

3. In a blender with the center of the top removed to allow steam to escape, blend the soup in batches until smooth.  Return to the pot.

4.  Add the cheeses, salt, and dijon mustard.  Serve topped with green onions, bacon bits, and additional shredded cheese.