Make the Cajun Butter by all the spices to a bowl and whisking together. Blend the butter with the all but 2 tablespoons seasoning and set aside. Reserve the remaining seasoning mixture.
Remove the giblets from the inside of the turkey and reserve for graving, if using.
Pat the outside of the turkey skin dry with a paper towel and place in a roasting rack, breast side up, inside a large roasting pan.
Tuck the wing tips under the turkey.
Carefully loosen the skin by running your hand between the skin and the breast meat working your way down to the leg.
Take 1/4 of the cajun butter mixture and rub it, thoroughly, under the skin over the breast and leg meat being sure to coat as much of the turkey as possible. Repeat on the opposite side and then coat the remaining butter mixture over the skin being sure to cover the entire turkey.
Sprinkle the breast, legs and inside cavity of the turkey with the remaining cajun seasoning and tuff the cavity of the bird with the orange, lemon, apple, garlic and herbs. Truss the turkey by tying the legs of the turkey together with kitchen twine.
Roast the turkey on the lowest rack level of the oven at 500˚F in the oven for 30 minutes and then turn the oven temperature down to 350˚F and insert a probe thermometer into the thickest part of the thigh. Set the alarm on the thermometer to 161˚F. A 14-16 pound turkey takes approximately 2 to 2 1/2 hours of roasting time total. (You can also use an instant read thermometer, just remember to check the turkey before the 2 hour mark to avoid overcooking.)
Remove from the oven and cover with foil. Let the turkey rest for approximately 30 minutes before carving.
Notes
Be sure to allow the turkey to come to room temperature before roasting to ensure it's cooked evenly all the way through.Don't stuff your turkey with stuffing because the stuffing will need to be cooked to a safe temperature of 165˚F and will cause the turkey meat to dry out due to the extra cooking time.Let the cooked turkey rest for 30 minutes to 1 hour before carving to give the juices time to redistribute thought out the meat. Otherwise, you will have a puddle of juices on the cutting board and not in the turkey meat leaving you with dry turkey.