Mix all herb butter ingredients together & set to the side
Remove Prime Rib Roast from packaging and pat dry. (make sure to get all moisture off, as the butter has a hard time sticking if it is wet)
Liberally cover the meat on all sides and in between the meat and bones with the horseradish herbed butter.
Place seasoned meat (bone side down) directly on grill grates to roast. If you'd like to catch drippings to make a gravy our a jus, place a disposable aluminum foil pan under grates with root veggies and a little bit of liquid. Then place your Prime Rib over it, so that the drippings get caught in the pan. (If you are doing this in the oven, place Prime rib on a roasting rack in a roasting pan to catch the juices.)
Smoke/ Roast until the internal temperature of the roast reaches:RARE: 120 deg ~ Medium 130 deg On average it takes about 35min per lb for a bone-in Prime Rib to get to the Rare temperate goal
Remove Prime Rib from the smoker/ oven. Cover with foil and rest 15-20 min. While it is resting heat your Grill to HIGH or (a cast iron skillet on your stove to high heat). Sear roast on all sides until you reach your desired doneness:Rare: 130 deg ~ Medium Rare: 135 deg ~ Medium: 140 deg
Rest for 15 min before slicing... I have found that using a Brisket knife cuts my roasts the best.