8 skinless, boneless chicken breast halves
1 teaspoon white wine vinegar
1 onion, chopped
1 teaspoon chili powder
1 teaspoon dried rosemary
3 tablespoons brown sugar
1 teaspoon paprika
2 tablespoons grated Parmesan cheese
1 tablespoon lemon juice
2 teaspoons Worcestershire sauce
2 tablespoons butter, melted
Place chicken within 3 inches of the bottom of a large resealable plastic bag. Place bag in a large resealable plastic bag. Brush onions with vinegar, then chili powder, then rosemary. Place brown sugar, paprika, lemon juice, Worcestershire sauce and butter in bag. Seal.
Return bag to the resealable plastic bag. Seal and seal bag. Place plastic bag in plastic bag. Put plastic bag over bottom of resealable plastic bag.
Place sterilized utensils in resealable plastic bag. Pour ketchup over chicken.
Remove plastic bag from resealable plastic bag and let sit overnight.
In the morning, preheat oven broiler.
Bake chicken in preheated oven for 1 hour. Remove aluminum foil from plastic bag. Place plastic bag on bone side up in large resealable glass dish or large resealable plastic bag. Place chicken on plastic bag. Seal plastic bag around chicken.
In the evening, broil uncovered for 2 to 3 minutes to prevent internal juices from running out. Remove foil and pan. Heat 2 tablespoons butter over medium heat in a small skillet or mixing bowl over low heat.
Season with a pinch of salt and pepper to taste. Place chicken over plastic bag, secure with toothpicks. Place lid on metal broiler pan; broil until chicken is golden brown and juices run clear, about 25 minutes. Remove plastic bag and broil chicken with lid on pan for about 5 minutes to prevent internal juices from running out.