Preheat your oven to 400°F (200°C). Cut the top off the head of garlic, drizzle with olive oil, and wrap it in aluminum foil. Roast in the oven for about 30-35 minutes, or until the cloves are soft and caramelized. Let cool.

In a mixing bowl, combine the softened butter, roasted garlic cloves (squeezed out of their skins), chopped rosemary, and thyme. Season with salt and pepper. Mix well until fully combined. Transfer to a piece of parchment paper, shape it into a log, and refrigerate until firm.

In a small bowl, mix together the smoked mulato chili powder, crushed toasted coriander, kosher salt, black pepper, garlic powder, and onion powder. Rub the entire prime rib roast with olive oil and then generously coat it with the spice mixture, pressing it into the meat.

Preheat your smoker to 225°F (107°C). Place the seasoned prime rib on the smoker rack. Smoke for about 4-6 hours, or until the internal temperature reaches 130°F (54°C) for medium-rare. Use a meat thermometer for accuracy.

Once cooked, remove the prime rib from the smoker and let it rest for at least 20-30 minutes before slicing. This allows the juices to redistribute throughout the meat.

Slice the prime rib and serve with slices of the caramelized garlic compound butter on top. Enjoy!