Creamy Cauliflower Soup

I found a recipe for Cheddar Cauliflower Soup in one of my cook books and I lightened it up a bit by using milk instead of cream. I also used less butter and cheddar and added cream cheese to give it a rich flavor. It turned out great and it's only about 3 WW points for 1 cup!

1 T. butter
1 lg. onion, finely chopped
2 cans low sodium and 99% fat free chicken broth
1 head of cauliflower, separated into small florets
1 potato, peeled and coarsely chopped
1 t. salt
1/8 t. pepper
1 1/3 C. skim milk
3 T. low fat cream cheese, cubed(I use Weight Watchers)
1/3 - 1/2 C. grated cheddar cheese (I don't use low fat because it doesn't melt well)
Chopped chives, for garnish

In a large pot, melt the butter over medium heat. Add onion and cook 8 to 10 minutes or until translucent. Add chicken broth, cauliflower, potato, salt and pepper and bring to a boil over high heat. Reduce the heat and boil gently, stirring occasionally, until the cauliflower and potato are very tender, about 18 to 20 minutes. Remove the pot from the heat. In batches, puree the soup in a blender until smooth, or you can just use and immersion blender. Return the soup to the pot and stir in the cream cheese. When the cream cheese is melted, add the milk. Heat over medium-low heat until hot (do not boil), then gradually stir in the cheese until melted and smooth. Serve immediately, garnished with chopped chives.