How To: Cook a Prime Rib Roast


Nothing is better than a perfectly cooked prime rib roast. That buttery perfection that just melts in your mouth,  slices with the barest pressure of a knife, covered in a brown gravy, with a side of mashed potatoes and greens of some sort…culinary heaven.

And since I became emboldened by the fact that I own a meat thermometer, and prime rib roasts are affordable this time of year (not so many tears when I screw it up) I have roasted about 5 over the past year, and just did another one for Thanksgiving lunch this Saturday. Yes, a lunch. I worked all weekend evenings this long weekend, so my parents were kind enough to make a turkey feast for the kids and Mike, while I had hospital cafeteria food. So I think a prime rib lunch before one of my shifts was entirely deserved ;)

Ingredients Needed:

prime rib roast


Yup, that’s it. I don’t like any flavoring, salt, (which, by the way, dries out the meat you are cooking, big no-no) garlic rubs or the like. The butter has some salt in it of course, but the purpose is to actually help sear the meat at the beginning of the cooking process. You can search and try some rubs or toppings, there are a few out there, if you so desire.

Remove your roast from all its packaging and  let it sit out for an hour until it’s about room temperature. Never, ever, cook a roast from frozen. The outside will be overdone and the inside will be raw. Absolutely a mess.

Take the butter and cover not only the ends, but if you don’t have a layer of fat on the top, cover that as well. When choosing prime rib, you actually want a layer of fat on the top. This helps make the roast oh-so tender. This roast didn’t have a layer, it was butchered too close,  so I put a layer of butter on top.

Preheat your oven to 450 at this point.

Once it’s covered, place on a wire rack in a pan deep enough to catch the drippings.

Now we want to sear the roast. Place it in the 450 degree oven for about 20 minutes. This picture reminded me that *embarrassed cough* I need to clean my oven.

It should be nicely browned (seared) on the outside now. This in theory seals in all the juices, and to be honest, when I do it this way I hardly have any drippings for gravy. So it really must do something to hold in the juices. Now you can turn the oven down to 325 degrees and roast.

You cannot cook prime rib without a meat thermometer. You can’t. This masterpiece depends on a precise temperature, with it being pulled out of the oven at the exact right moment. This can’t be achieved without a thermometer. And to be honest, if you spend $50 on a roast, why on earth wouldn’t you pick up a $15 digital thermometer?

I measure on the outside where on the thermometer it will hit and put my fingers there.

Then keeping my fingers on the same spot, I put the thermometer in the middle of the roast until it reaches to where I measured. Make sense? Probably not. I usually just pretend I know what I am talking about.

Now place in the 325 degree oven for baking. Below are guidelines for roasting a prime rib roast. I wouldn’t waste the roast by going beyond medium rare personally. You want to pull the roast out a minimum of 10 degrees BEFORE you hit these temperatures. Once the roast is out, tent it with foil, and let it sit for about 20 minutes. The temperature will rise at least another 10 degrees if you cover it in foil. It also lets the juices set and flow back to the meat.

Prime Rib Roasting Internal Temperatures

Blue in the middle- 110 degrees – when the middle of the roast still “quivers”

Rare- 120 degrees in the middle

Medium-rare- 125- 130 degrees in the middle

Medium – 140 degrees in the middle. You don’t want it cooked this much.

Well-done- Don’t make me slap you for ruining a prime rib roast

So, you have pulled it out 10 degrees before it’s ready and tented it in foil for 20 minutes, right? Now it’s time to remove the bones. You want to slice along the curve of the bones just like below. I apologize for the poor, flashy picture. My husband isn’t that adept at my camera. It could be because I don’t share well. And definitely not my camera.

I know you all are wondering why I can’t do this and take a decent picture at the same time. I don’t know. I’m sorry. FAIL COOK.

And once again, not top quality pic.  Good help is so hard to find these days. I mean honestly, I feed the man, make him do the dishes and his own laundry, don’t share my camera or my chocolate, and am nice to him, and nada on the good pictures. Sigh.

”You can see though, how pink it is in the middle. This was actually done to between Blue and Rare in the middle, for the first time ever, and it was fantastic. But I like rare. For the average person, I would cook it to rare to medium rare and no more.


I enjoyed your recipe.....I think I love you...don't tell my wife! ;-)


I have tried A lot of recipes for prime rib, even science of cooking labs recipes. And This one is still my favorite ...Prime rib should be kept simple. Follow the Basics. And definitely the Thermometer. And no heavy salting . Great recipe.

Barbara Maring
Barbara Maring

Hi i wanted to share my way of preparing a  roast......i brush on mustard along with other spices & it came out amazing !   you should try it !!




Thank you for the very detailed instructions. I am cooking a 9 lb. roast for my family this Easter. With your help I'm sure it will be great.


ok, I have one in my freezer and will use this guide. After I buy a new thermometer, since mine met with an untimely demise in a sink.

thekitchenmagpie moderator

@Meatlover Ha ha! Glad that you liked the recipe!! ;)

thekitchenmagpie moderator

@Wistiu  Thanks! Yes, no salt. You can flavor afterwards if you want, but a nice gravy does the trick!