Cooking a prime rib roast perfectly entails selecting a high-quality grade of meat, employing the ideal cooking method and following the appropriate temperature guidelines. Select only meat graded USDA choice or USDA prime; the marbling of lesser grades of meat isn't sufficient in keeping the meat moist during cooking. Roast the prime rib at a low temperature. Roasting at a low temperature allows the roast to retain as much moisture as possible. Cook the roast to the desired doneness. An oven thermometer inserted in the center of the roast during cooking facilitates precise temperature monitoring.
Remove the roast from the refrigerator and allow it to stand at room temperature for one hour.
Tie the roast between the rib bones with kitchen twine. If preparing a boneless rib roast, tie at one-inch intervals.
Heat the oven to 450 degrees Fahrenheit. Coat the roast with olive oil and season to taste with kosher salt and freshly ground black pepper.
Insert the probe of a digital oven thermometer in the center of the roast and place the display outside the oven for easy monitoring. Place the roast on a wire rack placed over a sheet pan. Place the roast on the middle rack of the oven.
Roast the prime rib at 450 degrees Fahrenheit until it has a golden-brown exterior. Reduce the heat to 225 degrees Fahrenheit.
Roast the prime rib until it reaches an internal temperature of 120 degrees Fahrenheit for medium-rare, until it reaches 130 degrees for medium (approximately 2 1/2 hours), until it reaches 140 degrees for medium-well (approximately three hours).
Cover the roast loosely with aluminum foil and set it aside. Rest the prime rib for a minimum of 20 minutes before untying and serving.