Remove roast from the fridge and unwrap it on a cutting board.
Using a sharp boning knife, carefully cut the bones (in one piece) from the roast, being sure not to remove too much meat from the bones.
Season the roast all over generously with Garlic Junkie seasoning.
Between the roast and the bones, sandwich a big handful of fresh herbs and some extra Garlic Junkie seasoning.
Using kitchen twine, tie the bones back on to the roast, securing tightly.
Transfer the roast to a wire rack over a cookie sheet and place it in the fridge for at least one hour– and up to over night.
Preheat the Traeger grill to 225* with the super smoke feature.
Place the prepared roast in the grill, with the Meater thermometer inserted, and close the lid.
Set the desired temperature on the Meater app to 110*.
Allow the roast to cook until it reaches 110*.
Bump up the temperature of the grill to 400*, and leave the roast in the grill.
Adjust the desired temperature on the Meater to 120*.
Allow it to get very hot and sear the roast all over until the internal temperature eaches 120*.
Adjust the Meater temperature one more time to 130*.
Remove the meat from the grill, tent with foil and allow to rest until the desired temperature reaches 130*.
Slice with a sharp knife and serve with caramelized onion horseradish sauce.
While the roast is cooking, make the sauce.
Thinly slice the onion and cook in a saucepan with lots of butter until very soft, golden and caramelized.
In a bowl, combine the mayo, sour cream, horseradish sauce, cooked onions and shredded cheese.
Mix until well combined and season to taste.
Set aside and serve your Caramelized Onion Horseradish Sauce with your Traeger Smoked Prime Rib.