Cauliflower Soup

I made this soup for dinner tonight and everyone loved it- even Brian, who isn't necessarily a soup guy. I love that it has a lot of healthy ingredients in it and it makes a ton for leftovers.
Cauliflower Soup
Adapted from Zoom Yummy

1 head of cauliflower, chopped into florets
2 carrots, diced
1 onion, diced
3 Tbs. butter
7 cups chicken broth
4 Tbs. flour
3 cups milk
1 cup sour cream
1/2 cup sharp cheddar cheese
2 tsp. parsley
2 bay leaves
1/4 tsp. pepper
Salt, to taste

Melt 2 Tbs. butter in large saucepan. Saute onions for 3 minutes and then add carrots and saute for 2 additional minutes. Add cauliflower, chicken broth, and spices. Bring to a boil, reduce heat, and simmer covered for 25 minutes. While thats cooking, whisk together flour and milk in a bowl. Melt 1 Tbs. butter in smaller saucepan. Add milk and flour mixture and whisk together. Bring to a boil and whisk constantly, while boiling for two minutes. Add milk mixture to soup and simmer for 10 minutes altogether. Remove from heat and add sour cream and cheese. Serve.