To prepare a boneless rib roast in the oven, place it in an oven preheated to 450 F, sear it for 15 minutes and then cook for about two hours at 350 F. The roast is ready when the internal temperature is between 120 and 170 F.
Before placing it in the oven, pat the roast dry and rub the cut ends with butter. Season the outside with pepper to taste, and place the roast on a metal roasting rack uncovered with the fat side up to allow its juices to moisten the roast as it cooks.
After turning the oven temperature down, the approximate cooking time for a roast is about 12 to 15 minutes per pound. Start checking the internal temperature early, about 45 minutes before the roast is suppose to be ready to avoid overcooking.Take the roast out of the oven when the internal temperature reaches 120 F for rare meat, 145 F for medium-rare, 160 F for medium or 170 F for well done.
When it's ready, transfer the roast to a cutting board, loosely cover it with foil and let it stand for about 15 minutes. Don't let the roast set for too long; the residual heat of the oven raises the internal temperature about five degrees every 15 minutes. To serve, cut slices against the grain.