Let the prime rib come to room temperature for about two hours.
Preheat the oven to 450°F.
Season the roast with salt and fresh ground black pepper. Wrap the bones in foil to prevent burning.
In a mixing bowl, combine chopped rosemary, coarse black pepper, Dijon mustard, garlic powder, onion powder and kosher salt to make a paste. Rub this mixture over the meat.
Place the prime rib in a roasting pan.
Cook at 450°F for 30 minutes to sear the outside and lock in juices.
Reduce heat to 350°F and continue cooking until the meat thermometer reads:
110°F for medium-rare
120°F for medium
130°F for medium-well
140°F for well-done
Cooking time is approximately 15 to 20 minutes per pound.
Note: the roast will continue cooking after it is removed from the oven.
Let the roast rest covered with foil for 15 minutes before slicing.