The prime rib roast is a popular cut of beef. It's rich in fat, which adds flavour and moisture, and is a little-used muscle, which makes it a tender piece of meat. As implied by the name, you roast a prime rib roast to cook it, either in the oven or even on your grill. The key to cooking the best prime rib roast that you can is using a low temperature over a long cooking time. Keeping in mind that because the "best" roast depends largely on your own taste buds, how you season the roast will be key in truly making this the best. This recipe will just give you the best foundation technique.
Bring the prime rib roast closer to room temperature, or 21.1 degrees C, by letting it sit out on the counter for at least 1 hour, but no more than 3. This will help ensure the roast will cook evenly once it's in the oven or grill.
Preheat your oven or prepare your grill to 163 degrees C while the roast is still coming to room temperature
Trim some, but not all, of the fat from the prime rib. There should be no more than 1/2 inch of fat on the roast. Usually, excess fat will already have been removed.
Rub seasonings into the prime rib. These can include minced garlic, pepper, salt and Worcestershire sauce.
Calculate how long you will have to cook your roast. For rare, cook the roast for about 14 minutes per pound. For medium, cook the roast for about 16 minutes per pound. However, remember that these are general estimates.
Keep an instant-read meat thermometer nearby so you can check exactly what doneness the roast has reached. A flatter roast will cook more quickly than a round roast.
Place the roast in your roasting pan with the fatty side on top. Then place the roast in your oven. Alternatively, you can grill your roast, but you have to make sure your grill maintains a temperature of 163 degrees C. Charcoal grills tend to deliver a deeper, smokier flavour.
Check the roast's internal temperature with your instant read thermometer about 15 to 30 minutes before you calculated it would be done, just to make sure your estimated time is correct. Check the temperature every 15 minutes until the roast has reached the desired doneness. A rare roast is done when the thermometer reads 48.9 degrees C and a medium roast is done when the thermometer reads 54.4 degrees C.
Take the roast out of the oven and place it on a cutting board. Let it rest for at least 20 minutes, tented with foil.
Make gravy, or au jus, while the roast is resting. Skim the fat from the roasting pan, place the pan over medium heat on your range and add the beef stock to the pan. Reduce the gravy until it reaches the desired thickness, then season it with salt and pepper.
Serve the meat with the gravy after the roast has rested for at least 20 minutes.
Start with the best cut of meat to end up with the best prime rib roast. Look for a roast labelled Prime Grade, rich in marbled fat. The next best choice would be Choice Grade. Start the oven at 246 degrees C and cook your roast at that temperature for about 15 minutes before turning it down to 163 degrees C. This will, in essence, brown the roast, setting a crust around it that will help it retain juices.