Creamy Cauliflower Soup

2 medium onions, chopped
2 medium carrots, grated
2 celery ribs, sliced
2 garlic cloves, minced
1/4 cup plus 6 tablespoons butter, divided
1 medium head cauliflower, chopped
5 cups chicken broth
1/4 cup minced fresh parsley
1 teaspoon salt
1 teaspoon coarsely ground pepper
1/2 teaspoon dried basil
1/2 teaspoon dried tarragon
6 tablespoons all-purpose flour
1 cup milk
1/2 cup heavy whipping cream
1/4 cup sour cream
Fresh tarragon, optional

In a soup kettle or Dutch oven, saute the onions, carrots, celery and garlic in 1/4 cup butter until tender. Add cauliflower, broth, parsley, salt and pepper, basil and tarragon. Cover and simmer for 30 minutes or until the vegetables are tender.

Meanwhile, in a saucepan, melt the remaining butter. Stir in flour until smooth. Gradually stir in the milk and whipping cream. Bring to a boil; cook and stir for 2 minutes or until thickened.

Add to cauliflower mixture. Cook for 10 minutes or until thickened, stirring frequently. Remove from the heat; stir in sour cream. Garnish with tarragon if desired. Makes 8 servings (about 2 quarts).