Pre-warm your smoker to 450°F ready for the first part of the cook.
Prep the prime rib roast by making sure the bones are clean and then truss the meat with butcher’s twine.
Combine the herb and garlic compound butter ingredients in a bowl and mix thoroughly.
Place roughly chopped onion quarters, garlic and fresh herbs in a cast iron pan.
Place the rib roast bone side up in the pan and apply herb and garlic butter to this side, turn over and apply to the rest of the rib roast, including the sides. Rresere any leftover for later.
Place the rib roast in the smoker and cook at at 450° for 20 minutes.
After 20 minutes, apply the last of the herb and garlic butter to the top of the prime rib roast and lower the temp to 250°F.
Baste the rib roast every 30 minutes with the buttery juices from the pan.
Once the prime rib roast reaches an internal temp of 118°F, take it out of the smoker for a 20 minute rest.
While the rib roast is resting, place the cast iron pan over a high heat, add in the beef broth and red wine and simmer for 15 minutes and allow the sauce to reduce.
After 15 minutes, strain the sauce and add to a gravy jug.
Slice the prime rib roast into single rib eyes, remove the bones and slice into ¼” to ⅓” slices, drizzle with the red wine sauce and serve immediately.