Pat your prime rib dry with paper towels. In a small bowl, combine the kosher salt, garlic powder, onion powder and black peppercorns. In a separate bowl, whip up your magical flavor bomb – the garlic herb butter chipotle rub! Combine the softened garlic herb butter, smoked paprika, chipotle, and horseradish mustard. Mix well until fragrant and spreadable. Rub the mixture all over the prime rib, ensuring it gets into all the nooks and crannies. Then rub the spice rub over the butter mixture. Let the prime rib sit at room temperature for at least 3 hours - 24 hours.
Preheat your smoker or oven to 250°F. Place the prime rib on the smoker grate or oven and smoke for 3-4 hours, or until the internal temperature reaches 20° from your desired temperature range. Remove the oven. (Rare 120°-129°F, Medium Rare 130°F-134°F, Medium 135°-144°F)
Increase the smoker or oven temperature to 450°-500°F. Place the prime rib back on the smoker or in the oven and sear for an additional 10-15 minutes, or until a beautiful golden crust forms and the prime rib’s internal temperature has raised 10°F. Remove the prime rib from the oven. (Rare 120°-129°F, Medium Rare 130°F-134°F, Medium 135°-144°F)
Transfer the prime rib to a cutting board and let it rest for at least 20-30 minutes (after the temperature stops rising) before carving. This allows the juices to redistribute, resulting in an even more succulent and flavorful experience.