Preheat the oven to 350°F. Adjust a rack to the lowest position in the oven.

Line a roasting pan with aluminum foil and position a roasting rack inside of it.

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.

In a small bowl, stir the softened butter and olive oil together until mostly combined. It is okay if some pieces of butter are still visible.

With clean hands, rub the butter and olive oil all over the surface of the turkey, and under the breast skin.

Smash the garlic cloves with a back of a knife and discard the papery skins. Cut the lemon in half.

Place the garlic, onion, lemon, and herbs in the cavity of the turkey. 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.