Water, lightly salted
1 sm. onion, finely chopped
1/4 c. (1/2 stick) butter
1/4 c. flour
1 c. milk
1/2 tsp. salt
1 tsp. Worcestershire sauce
1 1/2 c. grated sharp Cheddar cheese
(6 oz.) 1 c. (1/2 pt.) dairy sour cream, room temperature
1/2 lb. bacon, crisp and crumbled, if desired

Preheat oven to 375 degrees (191 C). Butter a 2-quart casserole. Cook macaroni in lightly salted water according to package directions; drain. In a stainless steel, glass or enamel saucepan, saute onion in butter until transparent. Stir in flour. Cook 1 minute. Add milk. Cook, stirring until sauce thickens. Add salt, Worcestershire sauce and cheese. Heat, stirring until cheese melts. Empty sour cream into a large bowl. Gradually add sauce, stirring constantly. Fold in macaroni. Pour into casserole and sprinkle with bacon, if desired. Bake 25 to 30 minutes or until bubbly.

Makes 6 servings.

Variation:

Substitute 1/4 cup buttered bread crumbs, or 1/2 cup grated Cheddar cheese, for crumbled bacon, if desired.