Oven Barbecued Chicken
["6 skinless chicken breast halves (8 oz. each)", "1/3 c. chopped onion", "3/4 c. ketchup", "1/2 c. water", "1/3 c. white vinegar", "3 Tbsp. brown sugar", "1 Tbsp. Worcestershire sauce", "1 tsp. ground mustard", "1/3 tsp. salt", "1/8 tsp. pepper"]
["In a nonstick skillet coated with nonstick cooking spray, brown chicken over medium heat. Transfer to a 13 x 9 x 2-inch baking dish coated with nonstick cooking spray. Re-coat skillet with nonstick cooking spray; cook onion over medium heat until tender. Stir in the remaining ingredients. Bring to a boil. Reduce heat; simmer, uncovered, for 15 minutes. Pour over chicken. Bake, uncovered, at 350\u00b0 for 45 to 55 minutes or until chicken juices run clear and a meat thermometer reads 170\u00b0. Yield: 6 servings."]
["chicken", "onion", "ketchup", "water", "white vinegar", "brown sugar", "Worcestershire sauce", "ground mustard", "salt", "pepper"]