Spatchcocked Herb Chicken with Potatoes

Set the chicken breast-side down. With sturdy kitchen shears, cut along both sides of the backbone and remove it (save for stock). Flip the bird, splay the legs out, and press firmly on the breastbone with the heel of your hand until you feel it crack and the bird lies flat. Pat dry, then sprinkle about 16 g of the salt evenly over both sides. Refrigerate uncovered on a rack for at least 1 hour, or up to 24 hours for the crispest skin.

Heat the oven to 450°F (230°C) with a rack in the upper-middle position. Mash the softened butter with the garlic, thyme leaves, rosemary, the zest of the lemon, and plenty of black pepper. Slide your fingers under the skin of the breast and thighs to loosen it without tearing, then push most of the butter underneath and massage it out evenly from the outside. Smear the rest over the skin.

Toss the potatoes with the olive oil, the remaining salt, and pepper, and spread them in a single layer in a large rimmed sheet pan (about 33 × 46 cm / 13 × 18 in). Nestle the zested lemon, halved, cut-side down among them. Lay the chicken skin-side up on top of the potatoes, legs pointing toward the back of the oven. Roast 45–55 minutes, until the skin is deep golden and an instant-read thermometer in the thickest part of the thigh (not touching bone) reads 165°F (74°C); the breast should read at least 155–160°F (68–71°C).

Move the chicken to a cutting board and rest 10–15 minutes. Meanwhile, toss the potatoes in the pan juices and return them to the oven for 5 minutes if they need more crunch. Carve the chicken into legs, thighs, wings, and sliced breast, squeeze the roasted lemon over everything, and serve on top of the potatoes.