I've cooked Prime Rib a lot of different ways, smoked, rotisserie style outside, indirect on a gas, or charcoal BBQ, timed in the oven at a constant temp with a meat thermometer, encased in rock salt, and finally today's recipe which requires a little math to put together the correct cooking time. I actually like this one the best because it produces the great crust you expect when you dine out at a restaurant which specializes in Prime Rib.
This recipe if followed correctly produces perfect Prime Rib with little hassle.
1. Coat the Prime Rib with olive oil, kosher salt, rosemary, cracked pepper, onion powder, garlic powder, and diced fresh onion. Wrap in a plastic bag and let marinate overnight in the fridge.
2. Preheat oven to 500° degrees F.
3. It is easy to determine the exact cooking time to roast a prime rib by multiplying the weight of the roast by 5 minutes. Be as accurate as possible. Example: The prime rib roast weighs 5.53 pounds. Multiply 5.53 (pounds) times 5 (minutes) which equals = 27.65. This means the prime rib will roast for (27.65) or 28 minutes at 500° degrees F. After 28 minutes immediately turn the oven temperature off. Do not open the oven door during the next 2 hours the prime rib roast is still cooking.
(Make sure you take the Prime Rib out of the fridge 2-3 hours ahead of time so it can go into the oven at room temperature.)
This method will cook a perfectly medium rare prime rib, roasted to perfection producing a crispy outer crust and perfectly cooked throughout.