A prime rib roast is one of those things we have just infequently enough that I always need to refresh my memory on temperatures and timing. I trust Michael Smith when it comes to just about everything but the trouble is, we aren’t having the three or four bone prime rib that is often featured in his and other recipes. After resisting it (somewhat stubbornly) for years, I just use an oven safe digital thermometer now.

1. Pat the roast dry.
2. Rub the roast all over with onion powder, garlic powder, pepper, salt, paprika and marjoram leaves.
3. Preheat oven to 450F and set the oven rack at 1/3 from the bottom.
4. Insert your thermometer sensor to the centre of the roast and set it for 120F.
5. Bake for 30 mins then turn the heat down to 260F and continue cooking until your thermometer reads 120F.
6. Remove and tent with foil on a cutting board for at least 15 mins before carving.

I found this chart which at least helps in terms of a “workback schedule” for when your roast will be done.

Approximate weight	Temperature	Total Estimated Time	Temp Reading (Rare)
4 – 5 lbs.	450°/325° F	60 – 70 mins	120° F
7 – 8.5 lbs.	450°/325° F	1.5 – 1.75 hours	120° F
9 – 10.5 lbs.	450°/325° F	1.75 – 2.25 hours	120° F
11 – 13.5 lbs.	450°/325° F	2.25 – 2.75 hours	120° F