Cream of Cauliflower Soup

2 cup cooked cauliflower

2 cup liquid from cauliflower 

1/4 cup finely chopped onions

1 Tbsp. + 1tsp. butter

1 cup skim milk

1/2 cup yogurt

1 tsp. salt

1 tsp. pepper

2 Tbsp. chopped parsley

Combine 1 cup each cooked cauliflower and liquid in a blender or food processor. Cover; whirl until pureed. Repeat with remaining cauliflower and liquid. Sauté onions softened in butter in medium saucepan until softened but not brown, about 2 minutes. Add cauliflower puree; stir to combine. Stir in skim milk, yogurt, salt, and pepper.  Place over low heat until heated through. Sprinkle with parsley.