- Place the chicken on a cutting board, breast side down with the neck facing you. Using sharp kitchen shears, cut along one side of the backbone starting at the neck. Turn the chicken around and cut along the other side of the backbone down to the tail and remove the bone.
- Turn the chicken over breast side up. Place your hands over the middle of the breast and press down hard to flatten.
- Pat chicken dry with paper towel. Combine ingredients for marinade in a small bowl and stir well. Reserve ¼ cup of marinade and set aside. Place chicken on a large tray and brush with rest of marinade. Cover loosely with aluminum foil or plastic wrap and refrigerate for at least 1 hour.
- Set chicken out at room temperature and remove foil. Heat gas grill over medium-high heat (450ºF) for 10 minutes. In the meantime, combine ingredients for glaze in a sauce pan and whisk to combine. Heat over low heat until simmering. Stir and continue to simmer for 1-2 minutes until glaze is thick and sticks to the back of a spoon. Remove from heat and pour into a small bowl.
- Brush grill grates with cooking oil. Place chicken in the middle of grill with breast facing down. Grill for 5-7 minutes to crisp skin. Using grill tongs, carefully flip chicken and reduce heat to medium between 350-400ºF. Turn off the burner under the chicken. Brush chicken skin liberally with glaze. Continue to grill for 30-40 minutes (or until juice runs clear and internal temperature reaches 165ºF), brushing chicken again with glaze after 15 minutes.