One day ahead of time, place a wire rack inside a rimmed half sheet pan. Rub the rib roast all over with the salt, then place on the wire rack. Refrigerate for one day, completely uncovered. You can do this two days in advance if you prefer.
Two hours before cooking, remove the prime rib from the fridge, and let it stand at room temperature.
Preheat the oven to 250F.
In a small bowl, mix together the ghee, rosemary, thyme, and black pepper. Rub all over the rib roast, then place the beef with the bones underneath (see blog post photos if needed).
Cook the beef in the oven for about 3.5 to 3.75 hours, until the interior measures 120F, which will give you a medium rare interior after carryover cooking. I usually hit 120F at exactly 3.75 hours, but check earlier if you are unsure if your oven is accurate. (For rare, pull at 115F, about 3.5 hours, and for medium, pull at 125F, just under 4 hours).
Remove the beef from the oven and let it stand at room temperature for at least 30 minutes, and a max of 60 minutes. No need to cover with aluminum foil. During this time, I make yorkshire pudding or other sides in the oven.
Increase the oven temperature to as high as it will go, ideally 550F, but 500 is okay. Additionally, if you have a convection roast (or convection bake) feature, turn that on as well. When the oven is fully heated, return the rested beef to the oven for between 5 and 10 minutes, until thoroughly browned on the outside. In my oven at 550F with convection roast, 5 minutes is plenty to brown the exterior. I recommend turning the oven light on and watching it closely as it cooks. Do not brown for more than 10 minutes, or you'll start to increase the doneness on the interior.
The prime rib is now ready to slice and serve right away. There is no need to rest again. If desired, you can remove the bones before slicing by cutting right alongside them. I personally like to serve the pieces bone-in on the plate. Enjoy!
*The general rule of thumb for prime rib is to estimate 1lb per person. **A 10-lb roast usually has about 4 to 5 bones. I purchased choice grade.***As discussed in the blog post, I believe ghee to be the best choice here because of its neutral flavor, high smoke point, and consistency. You can make do with other types of fat if it's what you have, but I recommend ghee.