Mushroom Sauce
["2 Tbsp. margarine", "1 thin slice onion", "2 Tbsp. all-purpose flour", "1 c. beef broth", "1 (4 1/2 oz.) jar sliced mushrooms, drained", "1/4 tsp. salt", "1/8 tsp. pepper"]
["Heat margarine in an 8-inch skillet over low heat until melted.", "Cook and stir onion in margarine until onion is brown. Discard onion.", "Stir flour into margarine.", "Cook over low heat, stirring constantly, until flour is deep brown; remove from heat. Stir in broth and mushrooms.", "Heat to boiling, stirring constantly.", "Boil and stir 1 minute.", "Stir in salt and pepper and if desired, a few drops of Worcestershire sauce."]
["margarine", "thin slice onion", "flour", "beef broth", "mushrooms", "salt", "pepper"]