Foolproof Prime Rib Roast

I've had this recipe since around 1992.  I don't remember where I came across this recipe, but it makes a perfect prime rib.  For each additional pound of roast, increase each time in recipe by 12 minutes.

5 pounds prime rib roast

2 garlic cloves, minced (for each additional pound of roast add 1/2 clove)

Freshly ground black pepper

1. Early in the day, bring the roast to room temperature.  This is very important, so don't forget.  It can take several hours for a large rib roast to lose its cool.
2. Early in the day (say about 10:00 am) rub the entire surface of the meat with garlic and sprinkle liberally with pepper, then place in a shallow pan (or you can use a cast iron skillet).  Turn the oven to 375 degrees and as soon as the oven temperature has reached 375 degrees (I use an oven thermometer that can sit on the oven racks), place the roast in the oven, close the door, set your timer and cook for exactly one hour. 
3. When the hour is up, turn the oven off.  DO NOT OPEN THE OVEN DOOR.  Let the roast stay in the oven the remainder of the day.  Don't worry about spoiling, it won't, and don't worry, the residual heat will keep the roast cooking.  I repeat, do not open the oven door.
4. During this period, a large cut of meat will keep cooking on its absorbed heat longer than a smaller cut.
5. About 45 minutes before serving, turn the oven back on, and without opening the door, again set the temperature for 375 degrees.  The minute the temperature has been reached, start timing.
6. In 20 minutes, the roast will be pink in the middle and ready to take out of the oven.  For those who like beef ultra rare, cut the time to 10 to 15 minutes.  For a well done roast, allow 35 minutes.
7. After you remove the roast from the oven, let it rest on the counter for 10 minutes to seal in its juices before carving.

Makes 8 servings