How to Cook Prime Rib
You can expect to feed two people per pound with a boneless prime rib roast. Multiply the pounds of your prime rib by two and that’s approximately how many servings you have. When in doubt, lean on the heavier side of servings. It’s better to have more than enough than the other way around. Plus, leftover prime rib makes for a great sandwich the next day.
The best way to cook a boneless prime rib is by using the traditional method: Begin roasting at a high temperature for a short period of time, then reduce the heat to a lower temperature setting and continue at this setting for the remainder of the cook time.
Beginning the roast at a high temperature will help to develop a gorgeous crust, and reducing the temperature for the remainder of the cook time will give you more control over the final internal temperature of your roast.
It is important to note that the roast should be on a rack, not making any contact with the bottom of the pan. You can use a roasting rack fitted in a roasting pan or any oven-safe rack securely fitted on (or over) a sturdy, rimmed baking sheet. If using a baking sheet, line with foil so you can easily capture the drippings and transfer them to a saucepan to make a wonderful Au Jus sauce (recipe at the bottom of the page).
To begin, pat the roast dry with paper towels and score the fat cap. Scoring your roast will allow the fat to easily drip off the top of your boneless prime rib roast and also enable the seasoning to better enhance the flavor. Just scratch the surface in a checker board pattern with score lines approximately one inch apart.
Don’t waste your time overcomplicating prime rib seasoning. Prime rib has great beefy flavor, with gorgeous marbling and you should let it shine. All you need for a spectacular prime rib seasoning is Kosher salt and freshly ground black pepper. Seriously. That’s it.
There is no cook time chart that can guarantee a perfectly cooked prime rib — only your thermometer can do that. The internal temperature of your roast and cook time varies depending on a number of different factors. Just to name a few — the temperature of your roast when it goes into the oven, the exact size/thickness of your particular roast, altitude…and, the list goes on.
Invest in an instant-read thermometer. Instant read thermometers are digital, making them a breeze to read and giving you immediate results. They’re inexpensive and can be found at just about any grocery store.
If you have a thermometer that can stay in the roast while cooking in the oven — double bonus. You can actually set these thermometers to alert you once your roast has reached the desired temperature, giving you peace of mind and ensuring a perfectly cooked prime rib roast.
For best results, when taking the temperature of a boneless prime rib, insert the thermometer in the center of the thickest portion of the roast.
Also note, large roasts will continue to climb in temperature even after they come out of the oven, anywhere from 10-15°. This is why we suggest pulling your roast at 120° rather than 130-135°, which is a true medium-rare. Pull at 130° for medium doneness.
Many recipes and time charts will tell you to multiply the weight of your roast by 15 and this is your cook time (in minutes). However, as we discussed, there are multiple factors that will affect your cook time. So, to ensure you do not overcook your precious roast, we suggest you get a little more specific than that and take its temperature after just 1 hour and 45 minutes of cooking at 300°.
This time frame keeps you out of the “over-cooking” danger zone. Then, if you have not reached your desired temperature, subtract the current temperature from the desired temperature and multiply that number by 1.5. This is because while roasting at 300°, your prime rib will rise approximately 1° every 1 1/2 minutes, and this is where the “1.5” comes in.
Desired Temp. – Current Temp. = A
A x 1.5 = B
“B” is the number of minutes you will return your roast to the oven before checking its temperature once more.
Keep in mind that the ends of your prime rib are going to be more cooked than the center. So, if you have guests who prefer their prime rib with a little less red, you can always serve them the portions from the ends.
Remember, your prime rib is not finished cooking the moment you take it out of the oven. It will continue to rise in temperature as it rests. Resting the beef is important as it allows for the juice to redistribute throughout the roast instead of spilling out all over your carving board.
For a large roast like a prime rib, you should allow it to rest at least 15-20 minutes before carving. Great on it’s own or serve with Au Jus sauce (recipe below)
PRIME RIB AU JUS
Recipe adapted from: https://www.theanthonykitchen.com/boneless-prime-rib-recipe/