Let me show you the easiest most delicious way to cook the perfect prime rib roast. It seems intimidating, but is really both simple & forgiving! (Thank goodness, because it isn’t cheap.)
DRY: Pat the beef dry on all sides with some paper towels, then place it on a plate or tray in the refrigerator to air dry for at least 2 hours or up to overnight. This helps create a firmer crust and more of a bark-like finish on the exterior.
SEASON: Preheat the oven or your Traeger pellet grill to 225 F / 105 C. Sprinkle the prime rib evenly with salt and pepper, to taste, on all sides other than the bones on the bottom of the roast. Place the prime rib on a roasting tray with drip pan or on a wire rack placed on a rimmed baking sheet, resting on the bone-in sections with the fat cap facing up. Place a meat thermometer probe into the middle of the prime rib roast, pushing it mid way into the thickness of the meat & avoiding any bones. (On the Traeger, use the probes that come with the pellet grill; for the oven, an ideal model would be one that reads the temperature continuously and displays it outside the oven, so that you can avoid opening the oven repeatedly to check the temperature, like this one.)
ROAST: Place the prime rib in the oven or pellet grill and cook until the internal temperature of the prime rib is 120 F for rare or up to 130 F for medium rare, about 3 1/4 – 3 1/2 hours for rare and a little longer for medium rare. Start checking the internal temperature about a half hour out, so that you don’t miss that perfect spot. Remove the prime rib from the oven or pellet grill and take out the probe.
REST: Lay out two pieces of aluminum foil and carefully transfer the prime rib from the roasting tray. Place the beef on top of the foil and wrap it tightly; repeat for the second layer of foil. Wrap the foiled prime rib in a towel and place it in a large insulated cool bag if you have one. Rest the prime rib for 30 – 45 minutes, see notes.
BROWN: Preheat your oven or pellet grill to 450 F / 230 C. Remove the prime rib from the insulated cool bag & towel. Carefully unwrap the foil and pour off any juices, then transfer the prime rib back to a roasting tray or baking sheet. Cook until the exterior of the prime rib is browned and slightly crisped, about 15 minutes. (If your oven goes up to a higher temperature, you can also crank it up to 500 / 260 C – 550 F / 285 C and reduce the browning time to 5 – 10 minutes.)
CARVE: Remove the browned prime rib from the oven and let rest for 10 minutes. Snip off and discard the twine. Even with the roast being carved from the bone earlier, it will still have fused together while it cooked, so you will need to gently pull the roast from the bones, or cut it away if you’re nimble with a large knife! (Keep the bone section for making broth or picking over some other time.) Once the roast has been removed from the bone, lay it on a chopping board fat side up and carve. Serve your perfect prime rib immediately!
Ask your butcher to cut the roast from the bones, then re-attach the meat with twine – this makes it super easy to carve later. I’ve always found prime rib prepped like this at the grocery store, ready to go, but wanted to mention that just in case it isn’t universal!
This simple method can be adapted to larger pieces of prime rib, but will take longer. Follow the same instructions as above, but increase the cook time until the internal temperature reaches your preference. Rest & brown the prime rib just as in the instructions above.
You can rest the prime rib for longer, up to 90 minutes or so, if everything goes a little haywire on the day! If it goes any longer than that, you can also gently reheat the wrapped prime rib in a 225 F / 105 C oven until the internal temperature is where you like it. From there, rest and brown as per the rest of the recipe above.