Prime Rib of Beef (The infamous “Math Method”)

There are few things more daunting to the home cook than a prime rib of beef. But it really shouldn’t be. I stumbled on this recipe several years back and I can assure you the most perfect medium-rare roast.
Every.
Single.
Time.
INGREDIENTS:
1 Prime rib of beef
salt, pepper and garlic powder to taste
*note – this is where you’re allowed to go as crazy as you’d like. If you have a favorite dry rub, by all means use that.
DIRECTIONS:
Set the prime rib on a plate and bring it to room temperature. (Depending on the temperature of your fridge, this can take anywhere from one to three hours. Plan ahead).

Preheat oven to 500º.

Season roast liberally with salt, pepper and garlic powder.

This is where the math comes in, my friends.
Multiply the exact weight of the roast by 5. Round the resulting number up to the nearest whole number. Roast at 500º for exactly that many minutes.
(For instance, a six pound roast – times 5 = 30 minutes).

Then – turn the oven completely off. Do NOT remove the roast.
Do NOT (under penalty of whatever penalty you want to assess) open the oven door even a crack for two full hours.

Remove the roast and enjoy the most perfect medium-rare roast you’ve ever served.

**Note: Some newer stoves cool off faster than older stoves so this might not work as planned. Also, I understand that wall ovens are not the best for this recipe. But for those of you with older stoves (like moi) – enjoy!