Position a rack on the second-lowest level in the oven and preheat to 350°F.

Have ready a roasting pan large enough to accommodate the turkey when laid flat after spatchcocking (butterflying).

In a food processor fitted with the metal blade, combine the garlic, lemon zest, sage, thyme, salt, and pepper. Process until finely minced. Add the butter and process until well combined.

Place the turkey, still in its original wrappings, in a clean sink. Carefully slit open the plastic wrapper and remove the turkey. Remove the neck and bag of giblets from both the main cavity and neck cavity of the bird. Store them in a covered container in the refrigerator for making the gravy. Remove the plastic or metal clip holding the legs together. Pull and discard any fat pockets from the neck and main cavities of the bird. Trim off the tail, if desired, and store along with the neck and giblets for stock. Rinse the turkey and pat dry thoroughly.

To butterfly the turkey, place it, breast down, on a cutting board. Using poultry shears or a chef’s knife, cut through the turkey from one end to the other on each side of the backbone to remove it. Cut the backbone in half and refrigerate it for making stock for gravy. Turn the turkey breast side up, pull the body open, and use the heel of your hand to press down firmly, cracking the rib bones so the turkey lays flat. This takes a little pressure and strength; you might need to make a partial cut through the breast bone to get the turkey to lay flat.

Using your fingers, and being careful not to tear the skin, loosen the skin from the breast of the turkey to create a pocket. Smear the lemon-herb butter all over the breast meat under the skin with your fingers, pushing some butter over the thigh and leg meat. Rub the skin of the turkey all over with any remaining flavored butter and season on all sides with salt and pepper. Transfer to the roasting pan, laying the turkey out flat, skin side up.

Roast turkey for about 1 1/2 hours, depending on the size of the bird, until an instant-read thermometer registers between 160° to 165°F when inserted into the thickest part of the thigh. Make the giblet gravy while the turkey is roasting.

Transfer the turkey to a carving board and cover loosely with aluminum foil. Let rest for 20 minutes before carving, to allow the juices to redistribute. (The internal temperature will rise 5 to 10 degrees while the turkey rests.) Finish making the gravy while the turkey is resting.

Strain the juices and browned bits from the roasting pan through a fine-mesh sieve set over a large glass measuring cup. Set aside and allow the fat to rise to the top. Spoon off the fat. The pan juices can be added to the gravy.

Carve the turkey.

Serve the roast turkey accompanied by the Giblet Gravy (recipe is below).

Serves 8 to 12, depending on the size of the turkey