1 stick butter, divided
½ whole onion, finely diced
1 whole carrot finely diced
1 stalk celery, finely diced
1 large cauliflower heads, roughly chopped
2 tablespoons fresh parsley, chopped (fresh Italian flat leaf parsley is recommended)
3 tablespoons fresh thyme
2 quarts low-sodium chicken broth or stock
6 tablespoons all-purpose flour
2 cups whole milk
1 cup half-and-half
2-4 teaspoons salt, to taste
In a large soup pot or dutch oven, melt 4 tablespoons butter. Add the onion and cook for a few minutes until it caramelizes. Add the carrots and celery and cook an additional couple of minutes. Add cauliflower, thyme and parsley and stir to combine. Cover and cook over very low heat for 15 minutes. After 15 minutes, pour in chicken stock or broth. Bring to a boil, then reduce heat and allow to simmer.
In a medium saucepan, melt 4 tablespoons butter. Mix the flour with the milk and whisk to combine. Add flour-milk mixture slowly to the butter, whisking constantly. Remove from heat and stir in 1 cup half-and-half. Add mixture to the simmering soup. Allow to simmer for 15 to 20 minutes. Check seasoning and add more salt or pepper if necessary.
Just before serving, place the sour cream in a serving bowl or soup tureen. Add two to three ladles of hot soup into the tureen and stir to combine with the sour cream. Pour in remaining soup and stir. Serve immediately.
Recipe adapted from Pioneer Woman