Step 1Combine the salt, black pepper, garlic salt and cayenne pepper in a spice or coffee grinder and pulse until the spice blend has the consistency of sand. Store the spice blend in a sealed container in a cool, dry place up to 1 month.
Step 1Remove the neck and giblet bag from the turkey and save for another use. Clean the turkey cavity well under running water. Pat dry. Meanwhile, soak the folded cheesecloth in 1 cup melted butter until the entire cloth is saturated in butter.
Step 2Place the onion in the neck cavity of the bird. Season the bird with 4 tablespoons of the spice blend: Moisten your hands with olive oil and rub the seasonings all over the bird. Truss the turkey (if you do not know how to do this, at least tie the drumsticks together with twine).
Step 3Place the soaked cheesecloth on the roasting rack of a large, shallow roasting pan, then place the bird on the rack, breast-side down. Tuck the cheesecloth in around the sides of the bird.
Step 4Place the turkey into a cold oven and set the oven temperature to 475 degrees. After 25 minutes, baste the bird with melted butter. Repeat again after another 25 minutes.
Step 5Remove the roasting pan from the oven and reduce the temperature to 275 degrees. Carefully flip the turkey over in the pan so the breast is now on top. Lay the cheesecloth over the bird, and baste the cheesecloth with 2 cups chicken broth. Place the turkey back in the oven, basting every 45 minutes or so (if the juices thicken too much in the pan, baste with additional chicken broth). Continue to cook and baste until the turkey reaches 145 degrees in the thickest part of the breast, about 3 1/2 hours depending on the size of the bird. If too much liquid accumulates in the pan, use a turkey baster to remove the excess; do not let the turkey “swim” in liquid in the pan.
Step 66. Remove the turkey from the oven and increase the temperature to 450 degrees. Carefully remove the cheesecloth and paint the turkey lightly with mustard. Season with the additional 2 tablespoons spice blend. Place the turkey back in the oven.
Step 7Combine the remaining cup melted butter with the cider vinegar in a spray bottle. Remove the turkey from the oven every 15 minutes or so and spray the bird with the butter mixture. Continue roasting and spraying until a thermometer inserted in the thickest part of the thigh reaches an internal temperature of 160 degrees. Remove the turkey from the oven and give the bird one final spray.
Step 8Set the turkey aside for 20 minutes before slicing. Meanwhile, prepare the serving platter: Rub the garlic clove over a serving platter, releasing the oils, and sprinkle over a little salt and pepper. Drizzle over a little warm butter or olive oil and sprinkle over chopped chives and lemon zest.
Step 9Slice the turkey and place on the prepared platter. Serve immediately.