Servings: 2+

1 Prime Rib roast, 4½ lbs or larger 1 Prime Rib roast, 4½ lbs or larger
1 stick of butter, softened (optional) 1 stick of butter, softened (optional)
fresh herbs such as thyme or rosemary (optional) fresh herbs such as thyme or rosemary (optional)
salt (optional) salt (optional)

If you plan to butter the roast, mix the butter and fresh herbs the day before so that the herbs can infuse the butter. Keep the butter soft so that it can be spread on the roast when it's time to cook.
2 to 3 hours before starting cooking, take the roast out of the refrigerator. If wrapped, remove wrappings and pat dry with a towel. If you plan to season with salt, salt the roast. If you plan to butter the roast, spread the butter on the roast after salting. Let the roast sit loosely covered on the counter so that it can come closer to room temperature. It should not be left sitting for more than 3 hours and smaller roasts may warm up even faster.
Preheat the oven to 375°F. Place roast in a roasting pan (fat side up) and place pan in the oven, uncovered. Cook for 1 hour. Turn the oven OFF.
** DO NOT OPEN THE OVEN **. Leave the oven closed so that as much of the heat from the 1 hour cook is retained as possible. If you want to check on the roast, use the oven light only. Opening the oven door ruins the process.
45 minutes before you want to take the roast out for it's 15 to 20 minute rest, turn the oven back on to 300°F. Cook for 45 minutes. Take the roast out, let it rest for at least 15 minutes. Carve and enjoy.

I've used this method for roasts from 5 pounds (2 bones) through 12 pounds (5 bones) and it works about the same regardless of size. A smaller roast will be medium-rare to medium in the middle. A larger roast will be rare to medium-rare in the middle. If you like your meat a little more well done or have a larger roast, you can increase the initial cook time as that is the driving factor for doneness. A 10-15 minute increase would get a larger roast closer to medium-rare to medium. The second cook time is mostly to get the roast back up to temperature.  I've used this method for roasts from 5 pounds (2 bones) through 12 pounds (5 bones) and it works about the same regardless of size. A smaller roast will be medium-rare to medium in the middle. A larger roast will be rare to medium-rare in the middle. If you like your meat a little more well done or have a larger roast, you can increase the initial cook time as that is the driving factor for doneness. A 10 to 15 minute increase would get a larger roast closer to medium-rare to medium. The second cook time is mostly to get the roast back up to temperature.
The delay between turning the oven off and turning it back on can be as little as an hour or as long as 3-4 hours. The only requirement is that the oven door stays closed the entire time.  The delay between turning the oven off and turning it back on can be as little as an hour or as long as 3 to 4 hours. The only requirement is that the oven door stays closed the entire time.
One point to consider when planning to cook a roast this way is that your oven will not be available for any other dishes until the roast is complete. If you're planning a casserole or other baked dish, you will either need a second oven or may need to plan something that can finish cooking while the roast is resting.  One point to consider when planning to cook a roast this way is that your oven will not be available for any other dishes until the roast is complete. If you're planning a casserole or other baked dish, you will either need a second oven or may need to plan something that can finish cooking while the roast is resting.