In a small bowl, combine the coarse ground black pepper, coarse salt, garlic powder, ground coriander, celery seed, dried rosemary, and smoked paprika.
Add 1-2 tablespoons of olive oil onto the roast and spread evenly. Then, generously apply the spice rub until covered.
Using your hands, apply the compound butter you set aside and completely cover the roast.
Once the smoker is prepared and preheated to 225°F, put the prime rib roast directly on the smoker racks.
About 2 hours into the smoke, insert a digital thermometer into the middle of the thickest part of the roast. This will help ensure you don't undercook or overcook the meat.
Continue to smoke for another hour, or until desired doneness. Using tongs, remove the meat and let it rest for 10-15 minutes before slicing.
When slicing, each steak should be around ½ inch thick.
Once sliced, top each steak with a piece of refrigerated garlic herb butter.