All American Barbecue Sandwiches
["4 1/2 lb. ground beef", "1 1/2 c. chopped onion", "2 1/4 c. ketchup", "3 Tbsp. mustard", "3 Tbsp. Worcestershire sauce", "2 Tbsp. vinegar", "2 Tbsp. sugar", "1 Tbsp. salt", "1 Tbsp. pepper", "18 hamburger buns, split"]
["In a Dutch oven, cook beef and onion until meat is browned and onion is tender.", "Drain.", "Combine ketchup, mustard, Worcestershire sauce, vinegar, sugar, salt and pepper.", "Stir into beef mixture. Heat thoroughly.", "Serve on buns."]
["ground beef", "onion", "ketchup", "mustard", "Worcestershire sauce", "vinegar", "sugar", "salt", "pepper", "buns"]