Barbecued Beef
["2/3 c. chopped onion", "2 Tbsp. margarine", "3 Tbsp. vinegar", "1 1/2 Tbsp. Worcestershire sauce", "1 1/2 Tbsp. prepared mustard", "1/4 c. brown sugar", "1 1/3 c. catsup", "1 c. water or juice from roast", "1 qt. shredded or diced roast beef"]
["Keep heat gentle and stir occasionally for 30 to 45 minutes. Serve on buns (rye is especially good).", "Makes 10 servings."]
["onion", "margarine", "vinegar", "Worcestershire sauce", "mustard", "brown sugar", "catsup", "water", "beef"]