Whole Roasted Chicken, Spatchcocked

Ingredients

• 1 whole chicken, 3 1/2 to 4 1/2 lbs
• 1 tablespoon kosher salt
• 1 teaspoon baking powder
• 1 teaspoon black pepper, freshly ground
• 2 tablespoons unsalted butter, softened
• 1 tablespoon olive oil
• 4 cloves garlic, minced
• 1 tablespoon fresh rosemary, chopped
• 1 tablespoon fresh thyme leaves
• 1 lemon, zested, then cut into wedges
• 1 1/2 lbs small potatoes, halved
• 1 medium onion, cut into thick wedges

Method

1. Set the chicken breast-side down on a cutting board with the tail end toward you and pat it dry.
2. With sturdy kitchen shears, cut up one side of the backbone from tail to neck, staying tight against the bone. Cut up the other side and lift the backbone out. Save it — it goes straight into stock.
3. Flip the bird breast-side up, stack both palms on the center of the breastbone, and press down hard until the keel bone cracks and the chicken lies flat. That flat shape is the whole reason for the exercise: the thighs and the breast now sit in the same plane of heat.
4. Combine the salt, baking powder, and pepper and season the bird all over, including the underside. Set it skin-side up on a wire rack over a rimmed sheet pan and refrigerate uncovered 12 to 24 hours. The salt seasons past the surface and the dry air pulls moisture out of the skin — that is where crisp comes from, not from oil.
5. Preheat the oven to 450°F (230°C) with a rack in the upper third. Pull the chicken out while the oven comes up to temperature.
6. Mash the butter, olive oil, garlic, rosemary, thyme, and lemon zest into a paste. Slide your fingers under the skin over the breasts and thighs to loosen it, work most of the paste underneath, and rub the rest over the outside.
7. Toss the potatoes and onion with a little oil and salt and spread them on the sheet pan. Set the chicken on top, skin-side up, and tuck the wing tips behind the shoulders so they do not burn.
8. Roast 40 to 50 minutes, until the thickest part of the breast reads 157°F (69°C) and the thigh reads 175°F (79°C). Check both. The thermometer is the only honest answer in the kitchen.
9. If the skin is not deep brown when the temperatures hit, run the broiler 2 to 3 minutes and stand there watching it.
10. Move the chicken to a cutting board and rest 10 to 15 minutes. Carryover brings the breast to a safe 165°F (74°C) and the juices settle back into the meat. Cutting early dumps all of that onto the board.
11. Carve: legs and thighs first through the loosened hip joint, then run your knife down each side of the breastbone and lift the breasts off whole, then the wings. Slice the breasts crosswise.
12. Serve over the roasted potatoes and onion with lemon wedges, and spoon the pan juices over everything.