The Ultimate Guide to Cooking a Perfect Small Prime Rib Roast

How to Cook a Small Prime Rib Roast

Prime rib roast is a classic and flavorful dish that is often reserved for special occasions. However, cooking a full-sized prime rib roast can be a commitment due to its size and the effort required to prepare it. The good news is that you can easily cook a small prime rib roast without sacrificing flavor and tenderness. In this article, we will walk you through the process of cooking a small prime rib roast using the closed-oven method, providing step-by-step instructions and cooking tips.

What is a prime rib roast?

Before we delve into the cooking process, let’s first understand what a prime rib roast is. Prime rib refers to a classic roast beef preparation that comes from the primal cut of the beef rib. It is typically roasted on the bone and served with a simple sauce made from au jus, the meat’s natural juices. The term “prime” in prime rib roast indicates that the beef has been classified as prime by the USDA. If it is not labeled prime, it is known as a standing rib roast. In addition, if the roast is boneless, it is called a ribeye roast.
The term prime rib is based on the age of the cow from which the meat is taken and the amount of fat in the edible parts of the meat. Prime rib is known for its tenderness, juiciness, and flavor, with the intramuscular fat, also known as marbling, contributing to its juiciness and flavor. The grade of the meat is based on the amount of marbling, with more marbling resulting in a higher grade. To be considered prime, the cow must be between 9 and 30 months old.

Choosing the right size prime rib

When it comes to cooking a small prime rib roast, it’s important to choose the right size for your needs. A full-sized prime rib roast typically consists of 7 ribs and weighs close to 15 pounds, which can feed about 14 people or more, depending on their appetites. However, if you’re serving fewer people and don’t want to deal with excessive leftovers, a small prime rib roast is the way to go.
A small prime rib roast can weigh anywhere from 2 to 8 pounds, with the smallest size being enough to serve as few as 2 people with some leftovers. As a general rule, you can plan on 1/3-1/2 pound per serving, depending on the appetites of your guests.

The Closed Oven Method for Cooking a Small Prime Rib Roast

The closed oven method is an excellent technique for cooking a small prime rib roast weighing 4-8 pounds. This method ensures a perfectly medium-rare interior and a beautiful brown crust on the outside. Here’s a step-by-step guide to cooking a small prime rib roast in the oven:

  1. The night before cooking, unwrap the prime rib and let it sit uncovered in the refrigerator. This step will help dry out the surface, resulting in a nice brown color when roasted.
  2. Three hours before cooking, remove the roast from the refrigerator and place it on a sheet pan at room temperature.
  3. Thirty minutes before roasting, preheat the oven to 260°F (500°C) and season the meat generously with kosher salt and freshly ground black pepper.
  4. Calculate the cooking time based on the weight of the roast. Multiply the weight (in pounds) by 5 minutes to determine the total “active” cooking time at 500°F.
  5. When the oven is ready, place the roast on a rack in a roasting pan, fat side up. If desired, you can insert a meat thermometer into the deepest part of the meat for added accuracy.
  6. Place the roast in the preheated oven and roast for the calculated time.
  7. At the end of the cooking time, turn off the oven and resist the temptation to open the door. Leave the roast to rest in the oven for 2 hours.
  8. After 2 hours, remove the rib roast from the oven, carve, and serve immediately. If you used a meat thermometer, you will find that the internal temperature reaches the perfect medium-rare level of about 130°F (54°C).

Approximate cooking time for a small roast prime rib

To determine the approximate cooking time for a small prime rib roast at 500°F, multiply the weight of the roast (in pounds) by 5 minutes. For example, a 4-pound roast would require approximately 20 minutes of cooking time, while a 4.5-pound roast would require approximately 23 minutes. Keep in mind that cooking time may vary depending on the desired doneness.

Making Prime Rib Au Jus

Au jus is a flavorful sauce traditionally served with prime rib to enhance its flavor and juiciness. To make an easy prime rib au jus, follow these steps:

  1. While the prime rib is resting, pour the drippings from the roasting pan into a saucepan.
  2. Place saucepan over medium heat and add beef broth or stock.
  3. Bring to a simmer, stirring occasionally.
  4. Season the au jus with salt, pepper, and additional herbs or spices of your choice, such as thyme or rosemary.
  5. Allow the au jus to simmer for a few minutes to allow the flavors to develop.
  6. Remove the pan from the heat and strain the au jus to remove any solids.
  7. Pour the au jus into a serving jug or sauce boat.

Serve the prime rib with the au jus on the side for dipping or drizzling over the meat.

Tips for a Successful Small Prime Rib Roast

Here are some additional tips to ensure a successful small prime rib roast:

  1. Allow the roast to come to room temperature before cooking. Allowing the meat to sit at room temperature for a few hours will ensure more even cooking.
  2. Season your roast generously with kosher salt and freshly ground black pepper. These simple seasonings enhance the natural flavors of the meat.
  3. Consider using a roasting pan with a rack. The rack raises the roast, allowing hot air to circulate evenly around the roast for better browning and cooking.
  4. If using a meat thermometer, insert it into the thickest part of the roast without touching the bone for an accurate temperature reading.
  5. Resist the urge to open the oven door while the roast is cooking. Opening the door can cause heat loss and interfere with the cooking process.
  6. Allow the roast to rest after cooking. This allows the juices to redistribute throughout the meat, resulting in a more flavorful and tender roast.
  7. Carve against the grain for maximum tenderness.
  8. Serve the prime rib with your choice of side dish, such as roasted vegetables, mashed potatoes or Yorkshire pudding.


Cooking a small prime rib doesn’t have to be reserved for special occasions. By using the oven method, you can easily achieve a delicious and perfectly cooked roast in less time. Remember to choose the right size roast, calculate the cooking time accurately, and let the roast rest before carving. With these simple steps and tips, you can confidently prepare a small prime rib roast that will impress your family and guests with its flavor and tenderness. Enjoy!


What size prime rib is considered small?

A small prime rib roast typically weighs between 2-8 pounds, making it suitable for serving 2-6 people, depending on their appetites.

Can I use the oven method for larger prime rib roasts?

The closed oven method is best suited for small prime rib roasts between 4-8 pounds. For larger roasts, alternative cooking methods such as reverse searing or low and slow cooking may be more appropriate.

How do I determine the cooking time for a small prime rib roast?

To calculate cooking time, multiply the weight of the roast (in pounds) by 5 minutes. This will give you an approximate cooking time at 500°F for medium rare doneness. Adjust the time slightly for desired doneness.

Should I season the small rib roast in advance?

It is recommended that the Small Prime Rib Roast be seasoned with kosher salt and freshly ground black pepper at least 30 minutes before roasting. This allows the flavors to penetrate the meat and enhance its flavor.

Can I make au jus from the drippings of a small prime rib roast?

Yes, you can make a flavorful au jus by pouring the drippings from the roasting pan into a saucepan and adding beef broth or stock. Simmer the mixture with seasonings of your choice to create a delicious sauce to accompany the prime rib.

How should I carve a small prime rib?

To carve a small prime rib roast, start by cutting parallel to the rib bones to create individual bone-in slices. Alternatively, you can remove the bones first and then slice against the grain for maximum tenderness.