Trim any excess fat from the top of the roast, down to ¼ inch thick.
In a small bowl, combine the salt, pepper, garlic and harissa.
Rub this mixture on the ribeye roast.
Place the roast on the smoker, fat side up (bone side down) and close the lid.
Smoke until the internal temperature reaches 120°F for rare, or 130°F for medium.
Smoke 35 minutes per pound at 225°F for a rare roast, approximately 3.5 hours for a 6 lb roast.
Remove the roast to a cutting board, tent with foil and rest for 20 minutes.
Increase the temperature on your smoker to 400°F.
Place the roast back on the smoker and sear on both sides until the internal temperature reaches 130°F for rare, 135°F for medium rare or 140°F for medium. This should take about 10 minutes.
Remove the roast, back to the cutting board and let it rest for 15 minutes before slicing and serving.
Slice the bone from the bottom of the roast and set aside, or discard. Slice the roast into 1 inch slices and serve immediately.
Notes
Plan for 1 pound of uncooked meat per person. Once the meat cooks down and the bones are removed, this will equal closer to 1/2 pound of cooked meat per person.
I recommend a wood with a mild flavor, such as cherry or apple wood, for smoking the rib roast.
I recommend serving the prime rib with creamy horseradish. If you want to mix things up, you can combine one part horseradish to one part harissa paste for a flavorful sauce that pairs perfectly with this prime rib!