Low and Slow

• The first step in roasting a prime rib is to cook it at low heat -- typically between 200 and 250 degrees Fahrenheit -- until it reaches the desired degree of doneness. Although the U.S. Department of Agriculture recommends 145 F as the minimum safe temperature for beef, many people prefer prime rib cooked to a lower internal temperature. Cook the prime rib to 115 to 125 F for medium-rare, at which point, the meat will be deep pink and very juicy; 125 to 130 F for medium, for meat that's pink, tender and juicy; or 135 to 140 F for medium-well. Medium-well prime rib is slightly gray and somewhat drier. Keep in mind that the meat will continue to cook as it rests -- typically gaining 5 to 10 degrees in temperature. Use a meat thermometer to accurately gauge cooking time and check the roast frequently. You can always cook prime rib longer, but once it's overdone, there's no going back.

A Blast of Heat

• When the prime rib reaches the desired internal temperature, pull it from the oven immediately and set it in a draft-free place, such as the back of the stove. Tent the roast tightly with foil and wait 15 to 20 minutes. This resting period allows the juices to settle evenly throughout the meat, making for a juicier roast and easier slicing. In the meantime, preheat the oven to 550 F for the second step in cooking your prime rib. Uncover the roast and put it in the oven for 5 to 10 minutes, just to sear the meat and give it a crisp, caramelized coating. Allow it to cool for just a minute or two, slice it and serve.

Tips For Success

• The actual roasting of a prime rib takes only two steps, but there are a few things to consider before you put the roast in the oven. First, buy prime rib from a reputable butcher. When possible, buy a prime rib labeled "Prime" or "Choice." These grades, assigned by the USDA, indicate that the beef has a high degree of marbling, tenderness and juiciness. Most grocery stores sell "Select" grade beef, which won't be quite as tender. High-end butcher shops carry "Prime" grade, while some warehouse stores carry "Choice." Unwrap the meat and salt it a day or two ahead of time. Plan on about 1 tablespoon of salt per pound of beef. Cover the meat with plastic wrap and refrigerate it until you're ready to use it. Salting ahead of time takes just a few minutes, but makes for a juicier, more flavorful prime rib. Remove the roast from the refrigerator up to two hours before you cook it and allow it to come to room temperature on the countertop to ensure more even cooking.

The Equipment

• Make sure you have the right equipment before you begin roasting your prime rib. You'll need a large roasting pan with a V-rack on which to set the roast. The V-rack holds the roast just above the bottom of the pan so it cooks more evenly and the juices can collect in the bottom of the pan. A meat thermometer is absolutely essential to properly roasting a prime rib. Leave-in thermometers are helpful in giving you a general idea of when the roast is done, but they tend to be somewhat inaccurate. Double-check the reading by using an instant meat thermometer.