Preheat oven to 350 degrees F
Take the giblets out of the turkey. Remove any excess fat and leftover pinfeathers and pat the outside dry. Place the turkey in a large roasting. Season the whole turkey with kosher salt and black pepper. Stuff and the cavity with a bunch of thyme, halved lemon, quartered onion, and the garlic. Brush the outside of the turkey with the butter mixture and. Sprinkle with salt and pepper. Tie the legs together with string and tuck the wing tips under the body of the turkey.
Roast the turkey about 3 hours, or until the juices run clear when you cut between the leg and the thigh. Alternately, twenty minutes before roasting time is complete, begin to test for doneness with a digital probe thermometer inserted at the deepest part of the thigh. It is done when thigh registers 160 degrees. Add 10 minutes per pound for larger birds. Subtract 10 minutes per pound for smaller birds. Remove the turkey to a cutting board and cover with aluminum foil; let rest for 15-20 mins before carving.