Skillet Roast Chicken with Fennel, Parsnips, and Scallions

3 tablespoons olive oil, divided
1 3½–4-lb. chicken
Kosher salt and freshly ground black pepper
1 fennel bulb, sliced lengthwise ½” thick
2 large parsnips, peeled, sliced ½” thick on the diagonal
1 bunch scallions
3 wide strips lemon zest
Lemon wedges (for serving)

Preheat oven to 425°. Heat 1 Tbsp. oil in a large ovenproof skillet over medium-high. Season chicken inside and out with salt and pepper and cook, breast side down, until a beautiful golden brown. Use tongs to gently rotate chicken, being careful not to tear skin, and brown on all sides, 12–15 minutes total; transfer to a plate. Reserve skillet.
Toss fennel, parsnips, scallions, and lemon zest in skillet with remaining 2 Tbsp. oil; season with salt and pepper. Place chicken, breast side up, on top of vegetables. Roast until an instant-read thermometer inserted into the thickest part of chicken thigh registers 165°, 35–40 minutes. (You can also check doneness by cutting into thigh meat right at the joint. If the juices run clear, the bird is ready.) Transfer chicken to a cutting board and let rest at least 10 minutes before carving.
Serve chicken and vegetables with pan juices for spooning over and lemon wedges.