Thaw roast completely in refrigerator before cooking; allow 48-72 hours. Season roast with rub 12-18 hours before cooking and leave uncovered in refrigerator overnight.
When ready to cook, heat oven to 225° F. Place roast on elevated rack in roasting pan. Roast 2 hours, or to internal temperature of 120-125° F. Let roast rest 30-45 minutes.
Broil on high 2 inches from broiler, 4 minutes on one side, 2 minutes on other side, or until brown crust uniformly covers roast.