Step 1

Preheat oven to 425 degrees F. Place roasting rack on a rimmed baking sheet and coat with cooking spray.

Step 2

In a small bowl, combine barbecue sauce, peach preserves, and onion; mix well; reserve 1/4 cup for dipping.

Step 3

Place chicken breast side down on a cutting board. With a pair of poultry shears or a sharp knife, cut along both sides of the back bone, and remove the back bone. Flip chicken so that it is breast side up, and press firmly down in the chicken's center to crack the breast bone; this will allow the chicken to lay completely flat. Transfer chicken, breast side up, to a roasting rack.

Step 4

Spread butter evenly over the entire surface of the chicken. Sprinkle evenly with garlic powder, salt, and pepper.

Step 5

Roast chicken 45 minutes, then brush with half the barbecue sauce mixture and continue roasting 10 minutes. Brush with remaining barbecue sauce mixture and cook 5 to 10 more minutes or until no longer pink in center. Serve with reserved barbecue sauce mixture.