Cooking Guide for Semi-Boneless Beef Rib Roast

by Eric Mohrman
Just because it's called "prime" rib doesn't mean it's a USDA Prime-rated cut of beef.

Just because it's called "prime" rib doesn't mean it's a USDA Prime-rated cut of beef.

A semi-boneless beef rib roast makes a satisfying, flavorful meal. You can feed a crowd with this cut -- better known as prime rib -- by purchasing one rib for every two people. So, if you plan to have 12 dinner guests, buy a six-rib roast. While you're probably accustomed to first searing meat at a high temperature, then cooking it through gently and then resting it, do things a little differently for the juiciest, most evenly cooked prime rib. As crazy as it may sound, first slow-cook the meat, rest it and then sear it to develop the desirable crust.

Take the prime rib out of the refrigerator one to two hours before you plan to cook it. Blot it dry with paper towels, then pat sea salt or coarse kosher salt all over its surface; set it aside on the kitchen counter. This time period serves two important purposes: One, it brings the meat to room temperature so it cooks more evenly; two, it allows adequate time for moisture to be reabsorbed into the meat after the salt pulls it out and flavors it.

Set an oven rack one tier below the middle so your rib roast is approximately centered in the oven during cooking. Set your oven to 200 degrees Fahrenheit to preheat during the last 15 minutes of its time sitting on your counter.

Coat the surface of the beef to taste with freshly cracked black pepper or other desired seasonings, or let the flavor of the beef stand on its own. Other ingredients to use include dried rosemary or thyme, garlic or onion powder or a pre-mixed meat rub.

Place the prime rib on the rack of a sturdy roasting pan with the ribs down and the fat-side facing up. Put it onto the pre-set oven rack. Cook it for about 3 to 4 hours, with the cooking time varying considerably, depending upon the size of your rib roast. Starting at about 2 1/2 hours in for a three-rib roast or 3 hours in for a six-rib roast, monitor the internal temperature of the beef with an instant-read meat thermometer. Remove it from the oven as soon as it hits 135 F to cook it to medium, with a final temperature of 145 F, as recommended by the U.S. Department of Agriculture.

Turn the oven temperature up to its highest setting -- 500 or 550 F -- while resting the semi-boneless rib roast on a serving platter. During resting, its temperature continues to rise, and its internal juices settle.

Put the meat back on the rack of the roasting pan and return it to the middle of the oven after about 20 minutes. Cook it for about 6 to 10 minutes, just until the outside develops a crisp browning. Take it out and return it to the platter before serving.

Items you will need

  • Paper towels
  • Sea or coarse kosher salt
  • Black pepper and other seasonings (optional)
  • Roasting pan
  • Instant-read meat thermometer
  • Platter


  • Some cooks prefer to cook a semi-boneless beef rib roast to a different temperature than that recommended by the USDA. If you want yours rare, take it out of the oven the first time at 110 F for a final temperature of 120 F; for medium-rare, take it out initially at 120 F for a final temperature of 130 F; for medium-well, take it out at 140 F for a final temperature of 150 F; and for well-done, take it out at 150 F for a final temperature of 160 F.
  • Use the meat's drippings in the bottom of the roasting pan for flavoring a sauce or gravy.
  • "Semi-boneless" refers to the fact that a prime rib cut contains the rib bones but not any part of the backbone.


  • Meat cannot safely be held at room temperature for longer than 2 hours. Store meat below 40 F.

About the Author

Jon Mohrman has been a writer and editor for more than seven years. He specializes in food, travel and health topics. He attended the University of Pittsburgh for English literature and San Francisco State University for creative writing.

Photo Credits

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