Lamb Sirloin Roast Recipe - Cilantro Parsley (2024)

Published: Jan 7, 2021 · Modified: May 30, 2023 by Maxine Dubois · This post may contain affiliate links 1 Comment

This Lamb Sirloin Roast is made with lamb, garlic, olive oil, fresh rosemary, lemon juice, red wine and roasted to perfection.

There's something truly special about the aroma of succulent lamb infused with aromatic garlic, fragrant rosemary, and the subtle tang of lemon. The moment you set foot in your kitchen, you'll be captivated by the promise of a mouthwatering meal that is sure to impress family and friends.

Roasting a leg of lamb is an art that dates back centuries, with traditions passed down from generation to generation. The tender, juicy meat, with its rich flavors and tender texture, makes it a beloved centerpiece for festive gatherings or simply a Sunday feast shared with loved ones.

Whether you're a seasoned home cook or just beginning your culinary adventures, this recipe is accessible and guaranteed to deliver exceptional results. We'll share tips and techniques that will ensure your lamb roast turns out perfectly cooked, with tender meat that practically melts in your mouth.

If you love this recipe, you need to try my Grilled Lamb Chops Recipe or my Air fryer Rack of Lamb.

What is Lamb Sirloin Roast?

Lamb sirloin roast refers to a cut of meat taken from the lamb's sirloin region. The sirloin is a section located towards the rear of the lamb, between the leg and the loin. This particular cut is known for its tenderness, flavor, and relatively lean meat.

The lamb sirloin roast is typically boneless and can be prepared in various ways, such as roasting, grilling, or searing. It is often considered a prime cut of lamb, appreciated for its succulence and versatility in cooking. The meat from the sirloin region tends to have a fine texture and is relatively tender compared to other cuts.

Why you will love this recipe

• Exquisite Flavors: The combination of garlic, rosemary, and lemon in this recipe creates a symphony of flavors that beautifully complement the natural richness of the lamb. The garlic adds a savory depth, the rosemary provides earthy aromatics, and the lemon juice adds a refreshing brightness, resulting in a harmonious and well-balanced taste.
• Tender and Juicy Meat: The slow roasting method used in this recipe ensures that the leg of lamb remains incredibly tender and juicy. As the lamb cooks low and slow, the fat renders and the connective tissues break down, resulting in a melt-in-your-mouth texture that is absolutely irresistible.
• Impressive Presentation: A beautifully roasted leg of lamb makes for a stunning centerpiece on any dining table. Its golden-brown crust and succulent meat are visually appealing, making it an impressive dish for special occasions, celebrations, or gatherings with loved ones. Prepare to receive compliments and awe as you present this culinary masterpiece.
• Versatility: While this recipe highlights the classic flavors of garlic, rosemary, and lemon, lamb is also incredibly versatile. You can customize the flavors to suit your preferences by experimenting with different herbs, spices, or marinades. The tender meat of a roasted leg of lamb pairs well with a variety of side dishes, making it a versatile choice for any meal.

Lamb Sirloin Roast Recipe Ingredients

You'll only need a few simple ingredients to make this. The exact measurements are listed in the recipe card below. Here's an overview of what you'll need:

• Bone-in Leg of lamb
• Garlic
• Olive oil
• Rosemary
• Lemon juice
• Red wine
• Salt and pepper

See recipe card for quantities.

How to make Lamb Sirloin Roast

In a small bowl, mix together the crushed garlic, olive oil, chopped rosemary, lemon juice, red wine, kosher salt, and black pepper to create a marinade. Place the trimmed bone-in leg of lamb in a roasting pan or baking dish. Make several small cuts or slits in the lamb to allow the marinade to penetrate the meat. Pour the marinade over the lamb, making sure to coat it evenly. Use your hands or a brush to massage the marinade into the lamb, ensuring it is well-covered.

Cover the roasting pan or baking dish with aluminum foil and let the lamb marinate in the refrigerator for at least 2 hours, or overnight for even better flavor. Once marinated, remove the lamb from the refrigerator and let it sit at room temperature for about 30 minutes before cooking.

Preheat the oven to 325°F (165°C). Remove the foil and place the lamb in the preheated oven. Roast for approximately 20 minutes per pound of lamb, or until the internal temperature reaches your desired level of doneness. In this case, I roasted for an hour and 20 minutes. The recommended internal temperature for medium-rare lamb is 135°F (57°C). Halfway through the cooking time, baste the lamb with the juices from the roasting pan to keep it moist and flavorful.

Once cooked to your liking, remove the lamb from the oven and cover it loosely with foil. Allow it to rest for about 15 minutes before carving. This helps the juices redistribute within the meat for a more tender and flavorful roast. Slice the lamb into thin or thick slices, depending on your preference, and serve with the pan juices as a flavorful sauce.

What to serve with Lamb Sirloin Roast

• Mint Sauce or Jelly: Lamb and mint are a classic pairing. Serve a dollop of mint sauce or mint jelly on the side to add a refreshing and tangy element to each bite of the lamb.
• Roasted Vegetables: Roasting vegetables like potatoes, carrots, parsnips, and Brussels sprouts alongside the lamb roast brings out their natural sweetness and creates a harmonious combination. Toss the vegetables in olive oil, season with herbs, salt, and pepper, then roast until tender and golden.
• Creamy Mashed Potatoes: The smooth and creamy texture of mashed potatoes pairs wonderfully with the tender lamb. Season the mashed potatoes with garlic, butter, and herbs for added flavor.
• Couscous or Quinoa: Light and fluffy couscous or nutty quinoa can provide a satisfying and nutritious base for your lamb sirloin roast. Prepare them according to package instructions and add some herbs, spices, or roasted vegetables for extra flavor. Check out my Instant Pot Pearl Couscous.

Substitutions

• Bone-in Leg of Lamb: If you're unable to find a bone-in leg of lamb, you can substitute it with a boneless leg of lamb or lamb shoulder roast. Keep in mind that boneless cuts may have slightly different cooking times, so adjust accordingly.
• Garlic: If you don't have fresh garlic cloves on hand, you can use garlic powder or granulated garlic as a substitute. Use approximately 1 teaspoon of garlic powder or ½ teaspoon of granulated garlic per clove of fresh garlic.
• Olive Oil: Olive oil can be substituted with other oils such as vegetable oil, canola oil, or grapeseed oil. Choose an oil with a mild flavor that won't overpower the taste of the lamb.
• Rosemary: Fresh rosemary provides a distinctive flavor to the lamb, but if you don't have it available, you can use dried rosemary as a substitute. Use approximately ⅓ of the amount of fresh rosemary called for in the recipe.
• Lemon Juice: If you're out of fresh lemons or lemon juice, you can substitute it with white wine vinegar or apple cider vinegar. The acidity will still help enhance the flavors of the lamb.
• Red Wine: If you prefer to omit the red wine or don't have it on hand, you can replace it with beef or vegetable broth. This will help keep the lamb moist and add flavor to the roast.

Lamb Sirloin Roast Recipe Variations

• Moroccan Spiced Lamb Sirloin Roast: Create a flavorful North African-inspired dish by marinating the lamb with a mixture of spices like cumin, coriander, paprika, cinnamon, ginger, and turmeric. Add a touch of lemon zest and garlic to the marinade for extra depth of flavor. Roast the lamb to your desired doneness and serve it with couscous, roasted vegetables, and a drizzle of yogurt sauce.
• Herb and Mustard Crusted Lamb Sirloin Roast: Create an herby crust by combining chopped fresh herbs such as rosemary, thyme, and parsley with Dijon mustard, minced garlic, salt, and pepper. Spread the mixture evenly over the lamb before roasting it. The mustard adds tanginess while the herbs provide a fragrant and savory element.
• Balsamic Glazed Lamb Sirloin Roast: For a tangy and slightly sweet twist, create a balsamic glaze to coat the lamb. Mix balsamic vinegar, honey or brown sugar, Dijon mustard, minced garlic, and a pinch of salt and pepper. Brush the glaze over the lamb before and during roasting, allowing it to caramelize and create a deliciously sticky coating.

Check out my Baked Lamb Meatballs Recipe.

Equipment

• Roasting Pan: A sturdy and spacious roasting pan is essential for holding the lamb and catching any drippings during cooking. Choose a pan that is large enough to accommodate the size of your lamb roast.
• Roasting Rack: A roasting rack elevates the lamb off the bottom of the pan, allowing heat to circulate evenly around the meat. This helps promote even cooking and ensures that the bottom of the lamb doesn't become soggy.
• Meat Thermometer: A meat thermometer is crucial for monitoring the internal temperature of the lamb. This ensures that the lamb is cooked to your desired level of doneness. Look for a reliable instant-read thermometer that can be inserted into the thickest part of the roast.
• Carving Set: A carving set, including a sharp carving knife and a carving fork, is necessary for slicing and serving the lamb. A sharp knife ensures clean, precise cuts, while a carving fork helps hold the roast steady while you carve.
• Basting Brush or Spoon: A basting brush or spoon is handy for applying marinades, glazes, or pan juices to the lamb during the roasting process. This helps keep the meat moist and adds flavor.
• Aluminum Foil: Aluminum foil is useful for tenting the lamb roast during resting. It helps retain heat and allows the juices to redistribute within the meat for a more tender result.
• Oven Mitts or Heat-Resistant Gloves: Since the roasting pan and lamb will be hot, it's important to have oven mitts or heat-resistant gloves to protect your hands when handling the pan and removing the lamb from the oven.
• Kitchen Twine: Kitchen twine is used to truss the lamb if desired. Trussing helps maintain the shape of the roast and promotes even cooking. It involves tying the lamb with twine to secure the meat and any stuffing.

How to store Lamb Sirloin Roast

To store lamb sirloin roast properly, follow these steps:

• Let it cool: Allow the lamb sirloin roast to cool down to room temperature before storing it. This helps prevent condensation from forming inside the storage container and keeps the meat from becoming soggy.
• Wrap tightly: Wrap the lamb roast tightly in plastic wrap or aluminum foil to protect it from air and moisture. Ensure that the entire roast is covered, and there are no exposed areas.
• Use airtight container or freezer bag: If you prefer, you can transfer the wrapped lamb roast to an airtight container or a heavy-duty freezer bag. This extra layer of protection helps maintain the quality and prevents freezer burn.
• Label and date: Clearly label the storage container or bag with the date of storage. This will help you keep track of its freshness and ensure that you use it within a safe timeframe.
• Refrigerate or freeze: If you plan to use the lamb roast within a few days, store it in the refrigerator. Place it on a tray or in a shallow dish to catch any potential drippings. For longer-term storage, place the wrapped roast in the freezer. Frozen lamb roast can typically be stored for up to 3-4 months.
• Thawing: When ready to use a frozen lamb sirloin roast, transfer it to the refrigerator to thaw. Allow it to thaw slowly and completely before cooking. This can take several hours to overnight, depending on the size of the roast.

Lamb Sirloin Roast Recipe Top tips

• Bring the lamb to room temperature: Before roasting, allow the lamb to sit at room temperature for about 30 minutes to an hour. This helps promote more even cooking and ensures the lamb cooks more consistently throughout.
• Season the lamb generously: Season the lamb sirloin roast generously with salt and pepper, or your preferred seasoning blend. Don't be afraid to coat the meat thoroughly, as this enhances the flavor of the lamb.
• Use a meat thermometer: To achieve the desired level of doneness, it's highly recommended to use a meat thermometer. Insert it into the thickest part of the lamb, away from the bone, to ensure accurate readings. The internal temperature should be around 135°F (57°C) for medium-rare, 145°F (63°C) for medium, or adjust according to your preference.
• Let it rest: After removing the lamb from the oven, let it rest for about 10 to 15 minutes before carving. This allows the juices to redistribute within the meat, resulting in a more tender and juicy roast.
• Carve against the grain: When it's time to carve the lamb, remember to cut against the grain. This helps ensure each slice is tender and easier to chew.
• Make use of pan drippings: While the lamb rests, you can make a delicious sauce using the pan drippings. Skim off excess fat, then deglaze the pan with some wine or broth. Simmer and reduce the liquid until it thickens slightly. Strain the sauce, adjust the seasoning if needed, and serve it alongside the lamb.
• Pair with complementary flavors: Consider serving the lamb sirloin roast with complementary flavors such as mint sauce or jelly, roasted vegetables, garlic mashed potatoes, or a side of fresh salad. These accompaniments can enhance the overall dining experience and balance the richness of the lamb.
• Slice it right: To achieve consistent and appealing slices, use a sharp carving knife and a carving fork. Slice the lamb against the grain into thin or thick slices, depending on personal preference.

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Food safety

• Cook to a minimum temperature of 165 °F (74 °C)
• Do not use the same utensils on cooked food, that previously touched raw meat
• Wash hands after touching raw meat
• Don't leave food sitting out at room temperature for extended periods
• Never leave cooking food unattended
• Use oils with high smoking point to avoid harmful compounds
• Always have good ventilation when using a gas stove

See more guidelines at USDA.gov.