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Costco Boneless Leg of Lamb Recipe: Slow Roasted to Perfection

Discovering the Costco Boneless Leg of Lamb Recipe

If you’re on the hunt for an impressive main course that’s both delicious and easy to prepare, look no further than this Costco boneless leg of lamb recipe. Perfect for Easter dinner or any special occasions throughout the year, this recipe will have your guests asking for seconds (and possibly thirds!). The secret lies in slow-roasting the lamb to perfection, resulting in a tender, flavorful meat that’s sure to steal the show at the dinner table.

A costco boneless leg of lamb roast sitting on a cutting board with fresh herbs and garlic cloves scattered around it.

The Importance of Room Temperature

Before you start cooking lamb, it’s crucial to let it reach room temperature. This rule of thumb applies to any cut of lamb, whether it’s a whole leg of lamb, boneless lamb roast, or lamb chops. By allowing the lamb meat to warm up, you’re ensuring even cooking throughout the entire roast. So, next time you’re preparing to follow the Costco boneless leg of lamb recipe, remember to take your lamb out of the fridge at least an hour before you start cooking.

A boneless leg of lamb sitting on a counter, reaching room temperature.

Prepping Your Boneless Leg of Lamb

After your lamb has reached room temperature, it’s time to prepare your boneless leg of lamb. Start by patting the lamb dry, then generously sprinkle it with salt, black pepper, and garlic powder. Take a small bowl and mix together some lemon juice and lemon zest. This zesty mixture will add a great flavor to your lamb. Rub this mixture all over the lamb, ensuring it gets into all the nooks and crannies. You can even use fresh garlic for an extra punch of flavor.

A boneless lamb leg being rubbed with lemon zest, lemon juice, and spices.

Choosing the Best Cooking Method

When it comes to cooking your Costco boneless leg of lamb, you have a few options. The best way depends on the cooking equipment you have at your disposal. If you have a slow cooker or an instant pot, these are both excellent choices. Both methods result in a tender lamb that’s full of flavor. If you prefer a more traditional route, roasting in a preheated oven is also a fantastic option. No matter which method you choose, an instant-read thermometer is your best friend to ensure the perfect internal temperature.

A boneless leg of lamb roast in a dutch oven, ready for roasting.

Ensuring the Perfect Cooking Time

Ensuring the perfect cooking time for your lamb is key in this Costco boneless leg of lamb recipe. A common mistake is to overcook the lamb, which can result in tough, dry meat. Instead, aim for an internal temperature of around 145 degrees F. for medium-rare lamb. Always use a meat thermometer to check the temperature in the thickest part of the lamb. Remember, the lamb will continue to cook even after you take it out of the oven, so it’s always better to err on the side of undercooking.

Creating Your Braising Liquid

While your lamb is roasting, it’s time to create your braising liquid. This flavorful liquid will not only keep your lamb moist during cooking, but it will also serve as the base for a delicious sauce. In a Dutch oven, combine chicken broth or beef broth, red wine, fresh herbs like thyme and mint, and some large chunks of fresh garlic. Heat this mixture over medium heat until it’s warm, then pour it over your lamb in the roasting pan. This will keep your lamb juicy and flavorful throughout the cooking process.

A dutch oven filled with chicken broth, red wine, fresh herbs, and garlic cloves, creating a braising liquid.

Letting Your Lamb Rest

Once your lamb has reached the desired doneness, it’s time to let it rest. This is a crucial step in the Costco boneless leg of lamb recipe that should not be skipped. Letting your lamb rest allows the juices to redistribute throughout the meat, leading to a juicier, more flavorful bite. Cover your lamb loosely with aluminum foil and let it rest on a cutting board for at least 15 minutes before serving.

A roasted boneless leg of lamb covered with aluminum foil, resting on a cutting board.

Pairing Your Lamb with the Perfect Side Dish

Now that your lamb is cooked to perfection, it’s time to think about side dishes. A Greek salad is a classic pairing for lamb, as the freshness of the salad complements the rich flavors of the meat. Tzatziki sauce is another great choice, adding a cool, creamy element to the dish. Or, for a heartier option, try some roasted potatoes or a warm, crusty bread to soak up the delicious pan juices.

A plate of slow-roasted leg of lamb served with a Greek salad and tzatziki sauce.

Enjoying Your Costco Boneless Leg of Lamb Recipe

There you have it! By following these steps, you’ll have a delicious, slow-roasted leg of lamb that’s sure to impress. Whether you’re cooking for Easter Sunday, a family meal, or simply trying a new recipe for the first time, we’re sure this Costco boneless leg of lamb recipe will become one of your favorite meats to prepare. Enjoy!

A beautifully set dinner table with the slow-roasted leg of lamb as the main course, ready to be enjoyed.

Succulent Costco Boneless Leg of Lamb Recipe

Succulent Costco Boneless Leg of Lamb Recipe

Yield: 6-8 Servings
Prep Time: 20 minutes
Cook Time: 1 hour 30 minutes
Resting Time: 15 minutes
Total Time: 2 hours 5 minutes

This recipe for a succulent Costco boneless leg of lamb is perfect for any special occasion or a fancy Sunday roast. The lamb is flavored with a fragrant herb paste and roasted to perfection, resulting in a flavorful, tender, and juicy dish that's sure to impress.


  • 1 Costco boneless leg of lamb (approximately 4-5 lbs)
  • 5 cloves of garlic, minced
  • 3 tablespoons fresh rosemary, chopped
  • 1 tablespoon fresh thyme, chopped
  • Zest of 1 lemon
  • 2 tablespoons olive oil
  • 1/2 cup dry red wine
  • Salt and black pepper to taste


  1. Preheat oven to 350°F (175°C).
  2. In a small bowl, combine minced garlic, chopped rosemary, thyme, lemon zest, olive oil, salt, and pepper.
  3. Untie the lamb and rub the herb paste all over it, then roll it back up and secure with kitchen twine.
  4. Place the lamb on a roasting rack in a pan, pour the dry red wine into the pan.
  5. Roast the lamb in the preheated oven for about 1.5 hours, baste the lamb every 20 minutes.
  6. Remove the lamb from the oven, cover it loosely with aluminum foil, and let it rest for about 15 minutes.
  7. Slice the lamb against the grain into thin slices and serve.


The cooking times can vary depending on the size of the lamb and your oven, so it's always a good idea to use a meat thermometer to check the internal temperature.

Nutrition Information:
Yield: 8 Serving Size: 1
Amount Per Serving: Calories: 350Total Fat: 25gSaturated Fat: 10gTrans Fat: 0gUnsaturated Fat: 13gCholesterol: 85mgSodium: 100mgCarbohydrates: 1gNet Carbohydrates: 1gFiber: 0gSugar: 0gSugar Alcohols: 0gProtein: 26g

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