Cream of Potato Soup

2 1/2 cups cubed potatoes
1 tablespoons chopped onion (or dry onion, reconstituted)
1 1/2 teaspoons salt
1 cup nonfat dry milk powder
1 tablespoon flour
2 tablespoons butter or margarine
4 cups liquid (cooking liquid from potatoes, plus water or milk)

Cover potatoes and onion with boiling water. Add salt and cook until tender. Drain and save the liquid. Mash potatoes, or put them through sieve; set aside. Add dry milk and flour to liquid. Beat until smooth. Add butter. Cook over low heat until slightly thickened, about 15 minutes, stirring to prevent sticking and lumping. Combine with potatoes and reheat. Serves 6.

(Source: "Basic Food Storage Cookbook," South Jordan Utah River Stake, 2003, pg. 48)