Whether you call it spatchcock or butterflied, this is a great way to cook a whole chicken. Removing the backbone and laying the chicken out like a book reduces the cooking time and the white and dark meat are done at the same time. This chicken is served with grilled roasted potatoes that are tossed with a chimichurri sauce. Serve the extra sauce on the side for chicken dipping!
Toss the potatoes in just enough olive oil to coat all sides. Sprinkle them with salt and toss to evenly season them.
Remove the chicken from the packaging and pat it dry with paper towels. Using poultry or kitchen shears cut along each side of the back bone and remove it. Turn the chicken breast-side up. Open the two sides of the chicken as if you were opening a book, and lay it flat. Break the breast bone by firmly applying pressure and pressing down—you may break a few rib bones in the process. Tuck the wing tip under the upper wing and place in a shallow casserole dish.
Set your Spark to 500°F and oil the grill grates. Brush the chicken all over with olive oil. Season lightly on both sides with kosher salt and black pepper. Place the chicken skin-side up in the center of the grill grates over the heat deflector plate and cook with the lid down. Place the potatoes around the perimeter of the grill. Grill for 40-60 minutes or until juices run clear and the thigh registers 180˚F on your Spark temperature probes.
Remove the chicken from the grill and let rest 10 minutes. Cut chicken into halves or quarters and serve.
While the chicken and potatoes are cooking, make the Chimichurri Sauce: Place all the ingredients in a blender and pulse until well chopped and combined. It will have a beautiful green color and look like parsley pesto.
Remove the chicken from the grill and let rest, tented with aluminum foil, for 10 minutes. Remove the potatoes from the grill and toss with the Chimichurri Sauce while they are still warm so that they will absorb all the flavors. Cut the chicken into halves or quarters and serve.