Step 1

Season chicken all over inside and out with salt and pepper (make sure to get in and around every nook and cranny; about 4 tsp. Diamond Crystal or 2½ tsp. Morton kosher salt). Place on a wire rack set inside a rimmed baking sheet and let sit at room temperature while you make the garlic butter, or chill, uncovered, up to 1 day. If chilling, let sit at room temperature 1 hour before roasting.

Step 2

Place a rack in middle of oven; preheat to 325°. Coarsely chop 4 green garlic stalks; transfer to a food processor. Pulse until very finely chopped. Add butter and zest and pulse until almost smooth. Cut remaining 4 green garlic stalks in half lengthwise; set aside.

Step 3

Pat chicken dry again with paper towels (this will help the butter adhere and get the skin nicely browned). Smear garlic butter all over chicken. Gently lift the skin on the breast away from the flesh and rub some butter inside.

Step 4

Toss reserved green garlic and oil in a large cast-iron skillet or 13x9" baking dish to coat; season with salt. Tie chicken legs together with kitchen twine and tuck wings underneath back. Place chicken, breast side up, on top of garlic in skillet.

Step 5

Roast chicken, rotating pan halfway through for even browning, until skin is golden and an instant-read thermometer inserted into the thickest part of breast registers 155° (don’t worry; temperature will climb to 165° as the chicken rests), 80–90 minutes. Let chicken rest at least 20 minutes and up to 45 minutes.

Step 6

Transfer chicken to a cutting board and carve as desired. Serve with roasted green garlic alongside.