1 medium-sized head cauliflower
2 c. water
1 tsp. salt
7 tbsp. butter
7 tbsp. flour
1 qt. milk, warmed
1/2 c. sour cream, at room temperature
Salt & pepper to taste
1 c. Cheddar cheese

Cook cauliflower in boiling salted water until tender. Drain, reserving liquid. Mash about half the cauliflower and chop the rest in small pieces. Melt butter in heavy kettle, add flour and cook over low heat, stirring constantly until flour just begins to color. Do not brown it. Slowly add warm milk, stirring continuously until the mixture is smooth. Add cauliflower and heat until the soup is thick and creamy. Stir some hot soup into sour cream to warm it, then stir it into soup. Add some reserved broth if it is too thick. Season. Serve immediately, topping with grated cheese.