Christmas Dinner: How To Cook a Prime Rib Roast

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collage of Cooking a Prime Rib Roast
Slicing a Prime Rib Roast in a Plate

I revisit this post every Christmas! I am making the biggest. most beauteos prime rib roast I have ever bought on Boxing Day, using the method below. I don’t mess with the meat: no rubs, no flavoring nuttin’. Plain old butter to sear the meat and then a gravy made out of it’s own juices.

I am drooling just thinking of it!

Prime is the “grade” given to the meat, most roasts are actually just rib roasts, which on their own are delicious.

In Canada, we have Canada Prime, AAA, AA, and A. In the United States, they have Prime, Choice, Select and Standard.

It goes without saying that not all of us can get to a real butcher, so when looking for a roast, look for one that is well marbled, bright red meat and calculate one rib per two people (or 1/2 pound of meat). We always go slightly more because the leftovers are amazing.

Ingredients Needed:

prime rib roast

prime rib roast and butter in a wooden tray


Yup, that’s it. I don’t like any flavoring, salt, 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.

covering the roast with butter

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

prime rib roast covered with butter in a wire rack with a deep pan 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.

Prime Rib roast in a wire rack with a pan inside the 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.

prime rib roast nicely browned on the outside

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.

measuring the temperature of the prime rib roast from oven using the thermometer

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.

oven baked prime rib roast ready for roasting

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.

removing the bones of roasted prime rib

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.

Slicing a Prime Rib Roast in a Plate

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Karlynn Johnston

I’m a busy mom of two, wife & cookbook author who loves creating fast, fresh meals for my little family on the Canadian prairies. Karlynn Facts: I'm allergic to broccoli. I've never met a cocktail that I didn't like. I would rather burn down my house than clean it. Most of all, I love helping YOU get dinner ready because there's nothing more important than connecting with our loved ones around the dinner table!

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  1. Debbie Semeniuk says

    I tried your method the first and only time that I have ever attempted to cook prime rib, and it was fabulous! Will be cooking anather one on Boxing Day. Thanks for all of your great and easy recipes!

    • The Kitchen Magpie says

      You are so welcome!! I am making prime rib on Christmas and this is the only method I EVER use. It’s tried and true and won’t ruin a roast that’s $$$$ !

  2. Lorie Williamson Potter says

    One question – do you roast it uncovered the entire time? Tia.

  3. Linda says

    We had a prime rib Christmas Dinner! Sobey’s on 51st Ave were so great with picking out the right meat. They even cut the bone off and tied them to the bottom of the roast. We put a rub on it and it was delicious and the leftovers were amazing! Yours looks just as delicious. Happy New Year!

  4. Debby says

    What a great post! The roast looks fantastic. My mother in law taught me this method thirty years ago and I have always cooked roasts this way! The only difference is that I do like medium to well done, I know that is a crime in Alberta! Hope you have a Merry Christmas!

  5. A Canadian Foodie says

    What a great lesson! It looks divine!
    Prime rib is the only way to go… YUM! It is my fav! I confess, I stuff mine with garlic and use my grandmothers old enamel roaster which creates an incredible crust – lid on at 350…
    And I do season it and cook it bone in… but, meat and butter? Sounds like heaven to me!
    Love this idea for boxing day!
    Merry Christmas, Karlynn!!!!
    And family!!!

    • Karlynn says

      I am sure yours is amazing too! Mike just doesn’t like anything too garlic, what’s with THAT? Can you just tell he’s not Ukrainian?

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