Skip to Content

How To Cook Costco Lamb Leg

I am going to show you How To Cook Costco Lamb Leg, Tender, boneless leg of lamb is just the thing for a cold winter’s day. The meat becomes impossibly moist, juicy, and flavorful when it is roasted with vegetables, herbs, and seasonings. Add mashed potatoes for an unforgettable dinner!

I use bone-in Costco lamb for this dish. I’ve included instructions for bone-in and boneless leg of lamb, so you can use whichever cut you can find. Both are tasty.

How To Cook Costco Lamb Leg
How To Cook Costco Lamb Leg

Ingredients That You’ll Need:

  • Lamb – It has a strong, earthy flavor. The cooking time depends on the cut and weight of the meat.
  • Onion, Celery, and Carrots – When roasted with these vegetables, the meat absorbs their mildly sweet, earthy flavors. There is nothing like the aroma of them all cooking together! Both yellow and white onions will work well in this recipe.
  • Orange – Fruit also contributes to the dish’s tantalizing aroma, tenderizing and adding sweetness.
  • Garlic – For this dish, keep 15 to 20 cloves on hand. This ingredient plays an important role in the pan gravy, so I would not substitute it.
  • Rosemary – With a complex flavor profile that pairs well with citrus, sweet, and peppery notes, this herb pairs beautifully with meat, carrots, and oranges. If needed, thyme or sage can be substituted.
  • Beef Broth – To tenderize and moisten the meat, we will roast it in a mixture of beef broth and water.
  • Flour – We will use this to thicken the leftover juice from the roast, making a mouthwatering pan gravy for our dish.

How To Cook Costco Boneless Lamb Leg?

  • Preheat: Preheat your oven according to the instructions for your chosen cut of meat.
  • Slice the Vegetables: Onion and orange should be cut into quarters. Garlic should be peeled and skinned. Slice the celery into uneven, large chunks. Combine with the carrots and rosemary in a pan.
  • Season the Meat: Salt and pepper the meat evenly, pressing and massaging the seasonings in. When using bone-in, lay the cut down with the bone side up. Add the beef broth and water to the roasting pan. Pour the olive oil over the meat at the end. Then cover the pan with a large piece of foil.

How To Roast Costco Bone-in Vs. Boneless Leg Of Lamb?

Boneless: Cook the meat according to its weight. Set your oven to 325°F for a cut weighing 4-7 lbs. Roast according to the desired doneness:

  • Medium Rare: Cook for 20 minutes per pound, until internal temperature reaches 145°F.
  • Medium: Cook for 25 minutes per pound, until internal temperature reaches 160°F.
  • Well-Done: Cook for 30 minutes per pound, until internal temperature reaches 170°F.

Bone-In: Please adjust according to how many pounds of meat you are cooking. Preheat the oven to 300 degrees.

Cover the pan and cook it for 4.5 hours if you have a 4 to 4.5 lb cut. To achieve a golden-brown crust, remove the cover and roast for 45 minutes longer. Roast covered for an additional hour if the meat is 6 to 6.5 pounds.

How To Cook Costco Lamb Leg
How To Cook Costco Lamb Leg

How To Make Pan Gravy For Costco Slow Roast Leg Of Lamb?

  • Remove the Veggies: Place the pan on your stovetop with all the juice and vegetables still inside. Remove the rosemary, orange, and vegetables.
  • Mash and Boil: Mash the roasted garlic with a fork or wooden spoon. Add this to the juices in the pan, then heat the juice until it begins to boil.
  • Thicken with Flour: Whisk in the flour in small increments until well combined. After that, simmer the gravy on low heat until it thickens.

Note: If your gravy is too thick, add a little water until you achieve the desired consistency. Mix in additional flour until it is as thick as you like. If desired, strain the herbs from the mixture.

What Can I Serve With A Roasted Costco Leg Of Lamb?

With this dish, I like to serve mashed potatoes! If you wish to serve the vegetables as a side, roast a separate batch of vegetables if you wish to roast them.

Recipe Tips

Boneless Leg of Lamb: Roast a 4-7 lb boneless leg of lamb in a 325°F oven for the following times:

  • Medium Rare (internal temperature 145°F) 20 minutes per pound
  • Medium (internal temp of 160°F) 25 minutes per pound
  • Well Done (internal temp of 170°F) 30 minutes per pound

For Bone-in Leg of Lamb: I use a 5.5-pound leg of lamb for this recipe, which serves about 6 to 8 people. The oven temperature should be 300 degrees.

  • A roast leg of lamb weighing 4 to 4.5 pounds can be covered for 4.5 hours and uncovered for 45 minutes or until golden brown on the outside.
  • Roast 6 to 6.5 pounds covered for 5.5 hours and uncovered for 45 minutes or until golden brown on the outside.

Feel free to eat the roasted vegetables when serving, but I find they can be a little overcooked myself serve the lamb with mashed potatoes.

How To Cook Costco Lamb Leg
How To Cook Costco Lamb Leg

Try More Recipes:

Costco Lamb Leg Nutrition Facts

Amount Per Serving ( 100g )

  • Calories 630
  • Total Fat 28g
  • Saturated Fat 10g
  • Cholesterol 30mg
  • Total Carbohydrate 68g
  • Dietary Fiber 10g
  • Sugars 5g
  • Protein 33g

Nutrition Facts Source: Source

How To Cook Costco Lamb Leg

Difficulty:BeginnerPrep time: 15 minutesCook time:5 hours 30 minutesRest time: minutesTotal time:5 hours 45 minutesServings:8 servingsCalories:630 kcal Best Season:Available

Description

I am going to show you How To Cook Costco Lamb Leg, Tender, boneless leg of lamb is just the thing for a cold winter’s day. The meat becomes impossibly moist, juicy, and flavorful when it is roasted with vegetables, herbs, and seasonings. Add mashed potatoes for an unforgettable dinner!

Ingredients

Instructions

  1. Preheat the oven to 300°F.
  2. Cut the onion and orange into quarters. Break up the head of garlic and remove the skin, or peel and prepare 15-20 cloves. Rough chop the celery and set it all in the bottom of a large roasting pan with the carrots and rosemary.
  3. Season both sides of the leg of lamb generously with kosher salt and black pepper. Place the bone-side up and pour the beef broth and water over it.
  4. Pour the olive oil over the lamb, cover with aluminum foil, and roast in the hot oven for 5 hours (See Note 2 for different weights and roasting times).
  5. Remove from oven and set aluminum foil aside. Flip the leg of lamb carefully, bat with pan juices, and roast, uncovered, for 45 minutes or until the outside is a rich, golden brown.
  6. Keep lamb warm on a serving plate covered with aluminum foil after removing it from the pan.

Notes

  • Boneless Leg of Lamb: Roast a 4-7 lb boneless leg of lamb in a 325°F oven for the following times:
  • Medium Rare (internal temperature 145°F) 20 minutes per pound
  • Medium (internal temp of 160°F) 25 minutes per pound
  • Well Done (internal temp of 170°F) 30 minutes per pound
  • For Bone-in Leg of Lamb: I use a 5.5-pound leg of lamb for this recipe, which serves about 6 to 8 people. The oven temperature should be 300 degrees.
  • A roast leg of lamb weighing 4 to 4.5 pounds can be covered for 4.5 hours and uncovered for 45 minutes or until golden brown on the outside.
  • Roast 6 to 6.5 pounds covered for 5.5 hours and uncovered for 45 minutes or until golden brown on the outside.
  • Feel free to eat the roasted vegetables when serving, but I find they can be a little overcooked myself serve the lamb with mashed potatoes.
Keywords:How To Cook Costco Lamb Leg
Nutrition Facts

Servings 8


Amount Per Serving
Calories 630
% Daily Value *
Total Fat 28g44%
Saturated Fat 10g50%
Cholesterol 30mg10%
Total Carbohydrate 68g23%
Dietary Fiber 10g40%
Sugars 5g
Protein 33g66%

* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.