My default method for roasting chicken involves smearing an herby, garlicky butter under the skin, so it's in direct contact with the meat. Then, I simply truss and roast at high heat for the first twenty minutes, lowering the oven temperature to 350 to finish.
While this process always results in juicy, tender legs, on one more than one occasion it has failed to yield the same results with the white meat, which remains forlornly attached to the bird, rejected until every last scrap of dark meat has been devoured. For some reason, the other week I decided to spend five extra minutes and spatchcock -- or butterfly -- my bird before applying the usual ministrations. A couple of snips with my kitchen shears, and the backbone was no more. Laid flat in the roasting pan, the breast and legs on an even plane, the chicken cooked in record time. When I cut into the breast, I could immediately see that it was juicy and succulent. For the first time in a long time, I chose white meat instead of dark.
In a small bowl, combine the butter, lemon zest, garlic, thyme, mustard, a teaspoon of salt and some pepper. Set aside.
Remove the gizzards from the chicken and discard. Pat the chicken dry with paper towels and set it on a cutting board. Flip it onto its breast and using sturdy kitchen shears, remove the backbone by cutting carefully down each side of the bone, starting at the tail end of the bird. The entire inside of the chicken should be exposed when you’re finished.
Sprinkle the cavity thoroughly with salt and pepper, and then flip the chicken over so that it lies flat. Trim any excess deposits of fat from around the cavity, and gently slide your fingers under the skin and ease it away from the meat, around both sides of the breast and both legs. Carefully smear the compound butter underneath the skin all over the meat, being careful not to break the skin. Reserve about a tablespoon of the butter, and then spread that evenly over the skin, followed by a generous sprinkling of salt and pepper.
Lay the chicken in a shallow roasting pan just large enough to accommodate it and put in the refrigerator for an hour or two (this will help the skin crisp more when you cook it).
When you’re ready to make dinner, heat the oven to 425 degrees and remove the chicken from the fridge. Roast for 20 minutes, then baste and decrease heat to 375. Cook for another 15 to 20 minutes, basting once again in the middle, until cooked. Let the chicken sit for a few minutes before carving; serve with the pan juices and some crusty bread or roasted potatoes for sopping them up.