To roast prime rib in the oven, begin by letting it sit, unwrapped, overnight in the refrigerator. This causes the surface of the meat to dry out, making it easier to form a golden crust when the meat is cooked.
Remove the prime rib from the refrigerator and let it sit at room temperature for three hours. Preheat the oven to 500 degree Fahrenheit and rub the prime rib generously with salt and pepper.
The cooking time for the prime rib depends on the weight of the cut. To calculate how long the prime rib should cook for, multiply the weight of the cut by five. So a 4 pound cut of prime rib needs 20 minutes to cook properly.
For bone-in prime rib, place the meat with the bone side down on a roasting tray. Use a roasting rack to elevate the prime rib if the cut of meat is boneless. Make sure to place the fat side facing up when roasting boneless prim rib cuts. Place the roasting tray into the oven and cook the meat for the calculated amount of time. Once the allotted time has passed, turn the oven off and leave the prime rib in the oven for two hours. Remove the roasting tray from the oven and serve the prime rib immediately.