Oven-Barbecued Chicken
["1 Tbsp. dry mustard", "1/4 c. water", "freshly ground black pepper", "1/4 c. white or cider vinegar or to taste", "3 Tbsp. vegetable oil (canola or safflower oil)", "2 Tbsp. chopped onion (optional)", "1/2 c. chili sauce or ketchup", "1 (2 1/2 to 3 lb.) frying chicken, cut into serving pieces, skinned and all visible fat removed", "3 Tbsp. Worcestershire sauce"]
["You will also need vegetable oil spray.", "Do not use vegetable oil spray near an open flame or a heat source.", "Read and follow directions on can before using."]
["mustard", "water", "freshly ground black pepper", "white", "vegetable oil", "onion", "chili sauce", "chicken", "Worcestershire sauce"]