Liberally season the turkey with the salt and black pepper, taking care to season the outside as well as the internal cavity. Set the turkey breast side up onto the roasting rack and tuck the wing tips underneath the body.

Remove the leaves from 2 stems of rosemary and finely mince. Reserve the remainder of the bunch.

Place the softened butter and olive oil in a medium bowl. Add the minced rosemary, the zest of both lemons, and the garlic powder. Stir vigorously with a fork until the mixture is mostly combined. It is okay if some lumps of butter remain.

Smash the garlic cloves with a back of a knife and discard the papery skins. Cut the lemons in half. Place the garlic, lemons, and rosemary in the cavity of the turkey.

With clean hands, rub the lemon-rosemary butter all over the surface of the turkey, and under the breast skin.

Pour enough chicken broth into the roasting pan to rise 1/2 inch up the sides of the pan.

Roast the turkey on lowest rack of oven until the thickest part of the breast or leg reaches an internal temperature of 165°F, 2-3 1/2 hours, depending on its weight. Rotate the pan halfway through the cooking time.

Check to see that turkey is done. Remove from oven or add time as needed.

Allow the turkey to rest on the roasting rack for 30 minutes. Transfer the turkey to a cutting board. Carve as desired, and serve.