Herb Crusted Smoked Prime Rib Recipe:
Step 1, get a good Prime Rib roast from wherever you get your meats - Costco, the butcher, the guy in the van on the side of the highway. No need to get bone in, boneless cooks up great, but if the roast has bones, the guys at the meat counter will cut the bones off and tie them back on for you if you ask.
For the crust: Get fresh herbs instead of canned/powered as much as possible: A full sprig of Fresh Rosemary, Time and Sage. Cut them up into tiny bits and put them in a big bowl, a little food chopper helps if you have one. Add about half to 3/4 of a cup of EV Olive Oil, enough to completely drown the herbs. Throw in a couple tablespoons of chunky salt like Maldon Flakes and crushed black pepper corns, then about a tablespoon each of garlic powder and onion powder. Mix it all up, it will be an oily goopy thick green mess. Add more Olive Oil if you think its too dry/thick. Rub it all over the prime rib, all sides but lots of it on top. You'll cook the roast bone side down. Let the roast sit with the crust in the fridge for a few hours before you cook it. A lot of the oil will drip off, that's ok. The roast should be mostly covered in green, especially on top of the fat cap.
For the smoker, you'll want to set it to cook at higher heat than low/slow style, like 350. As with all things BBQ, the cook time will depend on the size of the roast and the temp, but no piece of meat is more dependent on a good meat thermometer than prime rib is. Put the roast on the hot smoker and add smoke to your desired amount - I like a lot because it will only infuse the outside and the inner meat will not register much smoke flavor. You can cook Prime Rib low and slow and you may get a more evenly medium rare final product, but you won't get the herb crusty outer edge like this recipe does.
Its done when its done: Take it off the smoker when the meat thermometer reads 120-125 in the middle of the meat, it will DEFINITELY keep cooking and raise up another 5-15 degrees after you remove it. If you take it off when the thermometer reads medium rare (130-135) it will keep cooking and go way past that to medium well or worse. Don't ruin it by overcooking. I would say take it off at 120 and cover with foil, or take it off at 125 and don't foil it, you should end up right at a perfect 130-135 medium rare. Make sure your meat thermometer is accurate or you won't get good results. When you take it off the herb crust will be mostly blackened, no longer much green. Let it rest to soak keep the juices in the meat and carve right before serving.
Let it rest in a pan that will collect the juices that do drip out, you could go find an Au Jus recipe you like, but you won't need it, I don't bother. The roast should be juicy and crispy and the juices that drain into the pan can just be poured back over it when you slice it and serve it.
Good luck, show pics when you make it.
/Dave