This year, I’ve been all about creating Asian-style holiday dishes, like my Asian-style Thanksgiving turkey.
For Christmas, I wanted something similar. I also needed to use up the lemongrass in my garden, which is going into hibernation in the colder months.
A lemongrass prime rib roast felt like the perfect choice for Christmas dinner. It also requires less cleanup, is quite forgiving to season, and is absolutely divine!
You’ll just need to set aside time to marinate and about two hours to cook.
Lemongrass adds bright, citrusy, herbal notes that transform a simple roast into something unique and delicious.
Plus, using the leafy tops—often discarded—to create a fragrant roasting bed is practical, less wasteful, and makes the whole kitchen smell amazing.
But if you don’t have lemongrass, no problem! You can make the crust with whatever herbs you have on hand. Now is the time to ransack your pantry and use up what leftover dried herbs you have.
I’ve used dried basil, leftover Italian seasoning from spaghetti nights, or other dried herbs. They all work equally well.
What You Will Need to Make Prime Rib
Ingredients
To make the prime rib roast, gather the following ingredients:
- Prime rib roast: The star of the show. The natural marbling ensures a tender, juicy result. I got a boneless roast (about 5 lbs) from Costco.
- Lemongrass: Bright, citrusy, and aromatic. Use the tender white-green parts for a flavor-packed crust, and the leafy tops to form a fragrant roasting bed. I used a bundle of lemongrass which included about 5 large stalks. You can also use about 1 cup of frozen minced lemongrass that is typically sold in Asian markets.
- Olive oil: Acts as a glue to stick the lemongrass onto the roast for a flavorful crust. If you don’t have olive oil, use sesame oil to keep with the Asian theme or room temperature unsalted butter.
- Salt, sugar, black pepper, garlic powder, onion powder: Pantry staples that will marinate and flavor the prime rib.
- Five-spice powder: Adds an Asian warmth to the seasoning mix. Chinese five spice powder is a blend of star anise, cloves, Chinese cinnamon, fennel, and Sichuan peppercorns. The last spice can vary depending on brand. The Vietnamese version of five spice blend that I like to use doesn’t include Sichuan peppercorns but regular black pepper or ginger powder, as I’m not a fan of the subtle tingling effect.
- Garlic: Adds deep, roasted flavor. Peel and leave the cloves whole to stuff into the roast for pockets of garlicky goodness.
- Yellow onion: Roasts alongside the lemongrass to add more aroma. Cut them in half only instead of slicing them smaller into wedges as I did originally. Smaller pieces caramelized quit a bit and burned at the bottom of the roasting pan.
Equipment
You will also need the following equipment for a successful roast:
- Cooking twine: Using cotton butchers twine is highly recommended to keep the roast compact. This helps it cook more evenly. I skipped this step on my initial try for simplicity, and the outside edges (cap) were more well-done than I liked. The next time I did it, it was perfect!
- Baking tray: A sturdy and deep tray makes it easier to move the roast in and out of the oven. One with a roasting rack is ideal for keeping the meat elevated, but it’s not necessary as you can use onions and lemongrass as a base too.
- Meat thermometer: To ensure a perfectly cooked prime rib without surprises, use a leave-in meat thermometer. Set your desired temperature, and it will beep when the roast reaches that target. It’s extremely important to insert the thermometer correctly to get an accurate read. Do not insert the thermometer from the top, as it can reach too low in the roast without you realizing it. Insert it from the side so the tip reaches the center of the roast.
- Oven mitts: Do yourself a favor and get a pair of extra-long silicone oven mitts. They’re practical, affordable, and make great gifts too. I had my husband take the roast out, and he badly burned his forearm reaching into the scorching oven. If only he had used my trusty mitts—the ones he got me over 15 years ago and still going strong.
How to Make Lemongrass Prime Rib
Step 1: Prepare the roast
Trim off excess fat, if needed, but make sure to still leave a good amount as it will keep the prime rib moist.
Clean off the prime roast by wiping it down with paper towels. Make small slits all over and stuff the garlic cloves inside.
In a small bow, mix together the salt, black pepper, garlic powder, onion powder, Chinese five-spice powder, and sugar. Rub this mixture all over the roast and into the slits.
Tie the roast tightly all around with cooking twine to help it hold its shape.
Step 2: Prepare the lemongrass and pan
Clean the lemongrass if using stalks by removing the outer leaves and trim off the rough leafy tops and set them aside. Mince the tender bottom stalks finely.
Rub olive oil over the roast and sprinkle the outside of the roast with the minced lemongrass. Transfer the roast to a bed of onions and the leafy lemongrass tops (if any). Cover and marinate in the fridge for one full day.
Step 3: Roast & Rest
Preheat your oven to 450°F. Place the prime rib in the oven and roast for 20 minutes. This high heat helps develop a flavorful crust. Then reduce the oven temperature to 325°F.
Continue roasting until the internal temperature of the meat reaches 120-125°F. At this stage, the roast is rare. This takes about 1 hour and 50 minutes which translates to about 22 minutes per lb.
Remove the roast from the oven and let it rest for 15 minutes. This allows the juices to redistribute, keeping the meat juicy and tender. During this resting time, the internal temperature will continue to cook and rise by up to 15°F, bringing the roast to 135-140°F, which is between medium rare and medium—my sweet spot.
Roasting Temperatures
When you have an expensive cut of beef, knowing when to take the roast out is crucial, as the internal temperature can rise by up to 15°F after it is removed from the oven. Overcooked beef is chewy. A no-no and a waste of money.
To prevent overcooking, take it out of the oven when it’s about 15°F below your desired final temperature.
- Rare: 120°F (take out at ~105°F)
- Medium rare: 130°F (take out at ~115°F)
- Medium: 140°F (take out at ~125°F)
- Medium well: 150°F (take out at ~135°F)
What to do if you undercook prime rib roast?
It is always better to undercook prime rib than to overcook it because you can fix meat that is too rare.
If the center is still too rare after slicing, return the slices back to the roasting pan. Bake at 350°F for about 5 minutes, or until it reaches the color you like, a lighter pink or no pink at all like a psychopath.
Asian-Style Au Jus Sauce
I personally don’t need an au jus sauce for my prime rib as I simply use the pan drippings as is to spoon over the slices.
But if you need a dedicated au jus sauce recipe, I’ve included a recipe below for an Asian-style version.
It’s made with pan drippings in addition to soy sauce and rice vinegar in place of the more traditional Worcestershire sauce, and finished with butter for a rich base.
Serve it warm on the side for guests who want an extra layer of flavor.
Lemongrass Prime Rib Roast with Asian-Style Au Jus Sauce
- Total Time: 25 hours 50 minutes
- Yield: 8–10 servings 1x
Description
Impress your friends and family with this herby and citrusy lemongrass prime rib roast. Great for the holidays or just because! Serve it with the optional Asian-style au jus for an extra layer of flavor.
Ingredients
Lemongrass Prime Rib Roast
- 5 lbs prime rib roast (boneless)
- 3 1/2 teaspoons fine ground sea salt
- 1 1/2 teaspoons ground black pepper
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- 1 teaspoon Chinese five-spice powder
- 1 teaspoon sugar
- 8 large lemongrass stalks or 1 cup minced lemongrass
- 1/3 cup olive oil or 1 stick/8 tablespoons unsalted butter
- 1 yellow onion (peel and halve)
- 1 head garlic (about 10–12 large cloves)
Asian-Style Au Jus Sauce (Optional)
- 1 cup pan drippings (or a combination of pan drippings and water or just beef stock)
- 2 tablespoons light soy sauce
- 1 tablespoon rice vinegar
- 1/2 teaspoon onion powder
- 1/2 teaspoon garlic powder
- 1/2 teaspoon ginger powder
- 1/8 teaspoon ground black pepper
- 4 tablespoon unsalted butter
- 1/4 teaspoon fine ground sea salt (or to taste)
Instructions
- Prepare the roast: Trim off excess fat, if needed, but make sure to still leave a good amount as it will keep the prime rib moist. Clean off the prime roast by wiping it down with paper towels. Make small slits all over and stuff the garlic cloves inside. In a small bowl, mix together the salt, black pepper, garlic powder, onion powder, Chinese five-spice powder, and sugar. Rub this mixture all over the roast and into the slits. Tie the roast tightly all around with cooking twine to help it hold its shape.
- Prepare the lemongrass and pan: Clean the lemongrass if using stalks by removing the outer leaves and trim off the rough leafy tops and set them aside (we’ll use them). Mince the tender bottom stalks finely. Rub olive oil or soften unsalted butter over the roast and sprinkle the outside of the roast with the minced lemongrass. Add onions and leafy lemongrass tops (if any) to the bottom of the roasting pan. Set the roast on top of this aromatic bed then cover and marinate in the fridge for 24 hours.
- Roast: Preheat your oven to 450°F. Place the prime rib in the oven and roast for 20 minutes. This high heat helps develop a flavorful crust. Then reduce the oven temperature to 325°F. Continue roasting until the internal temperature of the meat reaches 120-125°F (about 1 hour and 50 minutes). At this stage, the roast is rare. Remove the roast from the oven and let it rest for 15 minutes. This allows the juices to redistribute, keeping the meat juicy and tender. During this resting time, the internal temperature will continue to cook and rise by up to 15°F, bringing the roast to 135-140°F, which is between medium rare and medium.
- Make the Au Jus Sauce (Optional): In a medium saucepan, combine the pan drippings, soy sauce, rice vinegar, onion powder, garlic powder, ginger powder, ground black pepper, and butter. If you have roasted onions left in the roasting pan from making the prime rib, add those for extra flavor. Bring to a gentle simmer over medium-low heat and cook for about 5 minutes. Taste and add salt if needed. Strain out the solids and serve it warm alongside the prime rib.
