Rib roast should be room temp, take it out the fridge now! then do 5 mins x the total weight (8.55 lb roast = 42 min 45 sec, round up to 45 mins) at 500° F, then turn off the heat to the oven and let it rest for ~2 hrs in the oven until it comes to 120° F internal. do not open the oven during this period! When the 2 hours are up, its already rested and ready to slice.

Chef John's Method X