Preheat oven to 500 degrees, and place a low-sided oven-safe pan inside as it heats. Cast iron is preferable, but stainless steel also works.
Trim any excess fat from the prime rib roast and set aside.
In a mortar and pestle, combine the garlic cloves, peppercorns, rosemary needles, coriander seed, and fennel seed. Smash together until a paste forms. Add the remaining ingredients and combine until a uniform paste is achieved.
Evenly rub the paste on the outside of the roast. It should not be a thick coating. Place a wire-lead thermometer into the center of the roast.
Once the oven is up to temp, quickly remove the pan from the oven and close the door to prevent heat loss. Place the roast, bone-side down into the pan. Quickly place the pan back in the oven and roast for 10 minutes. Open the oven door and reduce the temperature to 350. Loosely lay a piece of foil over top the roast and close the oven door.
Roat to desired temperature - I find that 130 in the center tends to be safest for most crowds, delivering a good medium rare in the center and more medium toward the ends. For rare, remove at 115 or 120 internal. Carve and serve warm.