Preheat the Oven: Preheat your oven to 325°F (165°C). Position the oven rack on the lowest level to make room for the turkey.
Prepare the Turkey: Remove the neck and giblets from the turkey cavity. Rinse the turkey under cold water and pat it dry with paper towels.
Season the Turkey: Rub the softened butter all over the turkey, including under the skin if possible. Generously season with salt and pepper on all sides.
Add Aromatics: Stuff the turkey cavity with the onion, carrot, celery, fresh herbs, and garlic to add flavor from the inside as it roasts.
Truss the Turkey: Use kitchen twine to tie the turkey legs together, helping it cook evenly.
Place in Roasting Pan: Place the turkey breast-side up on a rack in a large roasting pan. Pour the chicken broth into the bottom of the pan to keep the turkey moist.
Roast the Turkey: Transfer the pan to the oven and roast, basting with pan juices every 30–45 minutes. Plan on 15 minutes per pound, or until the thickest part of the thigh reaches 165°F on a meat thermometer.
Rest the Turkey: Once cooked, remove the turkey from the oven, cover it loosely with foil, and let it rest for 20–30 minutes before carving.