Onion Crusted Prime Rib Roast


Onion Crusted Prime Rib Roast

Prep Time: 20 minutes

Start to Finish: Approximately 2 hours

8 servings


  • 1 (4 lb) boneless prime rib roast
  • 1/2 teaspoon garlic powder
  • 3 tablespoons minced dried onion flakes
  • Salt and fresh ground black pepper


Place beef, fat side up, on rack in a shallow roasting pan. Sprinkle all sides and underneath the beef generously with garlic powder, dried onion flakes, salt and pepper. Allow prepared roast to sit for at least 20 minutes before placing in the oven to roast.

Preheat oven to 450°F. Place roast uncovered in oven and cook for 15 minutes at 450°F. Then, lower temperature to 325°F for approximately 60 – 90 minutes or until meat thermometer inserted into the middle of the roast reaches 135°F (for medium). The temperature will rise approximately 5 – 10 ° F once it is removed.

Remove roast and let stand about 15 – 20 minutes before slicing. The temperature will rise slightly while it rests, so be sure to keep that in mind when considering cooking time and desired level of doneness.

Cooking Tips:

Roast should be at room temperature before roasting in the oven. Prepare the roast and allow it to sit in the pan with the seasoning on it for about 20 minutes or more before roasting. You never want to roast an ice cold piece of meat so be sure to let it sit out.

Don’t add water or any liquid to the pan.

Letting the roast rest after cooking before slicing allows it to retain its juices.

A bone-in roast may need a little more cooking time so be sure to check the internal temperature after 1 hour of roasting.

An instant-read digital meat thermometer makes it easy to get a fast an accurate reading on the meat temperature.

I think a prime rib is best served Medium Rare to Medium. I think anything over 160°F becomes dry and very over cooked, but here is the general rule.

My general rule for Internal Cooking Temperatures

  • Rare – Bright Red Center – Approx. 140°F, 63°C
  • Medium Rare – Medium- Approx. 145°F, 63°C
  • Medium – Well – Approx. 160°F, 71°C

Keep in mind that oven temperatures can vary so if you think your oven is not accurate, check the temperature by using an oven safe thermometer on the center rack in the oven and heat the oven for 15 minutes. Then check to see that your oven is reading the same temperature that it was set at. If it is off you will need to adjust your cooking time and temperature accordingly.

Leave a Reply

Your email address will not be published.


This site uses Akismet to reduce spam. Learn how your comment data is processed.