If you want a stunning roast that feels special but is surprisingly simple, a butterflied leg of lamb is the perfect choice. This guide will show you exactly how to cook butterflied leg of lamb in oven with plenty of garlic and herbs. It cooks faster and more evenly than a whole leg, and the flavor is incredible.
You get more surface area for a delicious crust. The inside stays tender and juicy. It’s a fantastic centerpiece for a Sunday dinner or holiday meal that will impress your guests without keeping you in the kitchen all day.
How To Cook Butterflied Leg Of Lamb In Oven
This method is straightforward. We will prepare a flavorful paste, coat the lamb, and roast it. The key is high heat for a beautiful sear, then finishing at a lower temperature. Let’s get everything you need ready.
What You’ll Need
Gathering your ingredients and tools first makes the process smooth. Here is your checklist.
- 1 butterflied leg of lamb (4 to 5 pounds). Ask your butcher to butterfly it, or buy it pre-prepared.
- 8-10 cloves garlic, minced
- 3 tablespoons fresh rosemary, finely chopped
- 3 tablespoons fresh thyme, finely chopped
- 2 tablespoons Dijon mustard
- 2 tablespoons olive oil, plus extra for drizzling
- 1 lemon, zested and juiced
- Kosher salt and freshly ground black pepper
For your tools, you’ll need a rimmed baking sheet or large roasting pan, a small bowl for mixing, and a sharp knife. A meat thermometer is essential for perfect doneness.
Preparing Your Lamb and Flavor Paste
Start by taking the lamb out of the fridge about an hour before cooking. Letting it come to room temperature helps it cook evenly. Pat it completely dry with paper towels. This step is crucial for a good crust.
While the lamb rests, make your garlic and herb paste. In a bowl, combine the minced garlic, chopped rosemary and thyme, Dijon mustard, olive oil, lemon zest, and juice. Mix it into a thick, fragrant paste. Season generously with salt and pepper—don’t be shy, as this is your main flavor layer.
Butterflying at Home (Optional)
If you have a whole leg, you can butterfly it yourself. Place it fat-side down on a cutting board. Use a sharp knife to cut horizontally through the thickest part, opening it like a book. Be careful not to cut all the way through. You want it to lay flat. Trim any excess fat or silver skin.
Step-by-Step Roasting Instructions
Now for the main event. Follow these steps for a perfectly cooked roast.
- Preheat and Prep: Preheat your oven to 450°F (230°C). Place a rack inside your baking sheet. This allows heat to circulate.
- Season the Lamb: Place the dried lamb on the rack, cut-side up. Drizzle lightly with olive oil and rub it all over. Season both sides liberaly with salt and pepper.
- Apply the Paste: Spread the entire garlic-herb paste over the top and sides of the lamb. Use your hands to press it in so it adheres well. Make sure to get it into any nooks.
- Sear at High Heat: Roast the lamb on the center rack at 450°F for 15 minutes. This creates a flavorful, browned crust.
- Lower the Temperature: After 15 minutes, reduce the oven temperature to 350°F (175°C). Do not open the oven door; just let the temperature drop naturally as it continues to cook.
- Roast to Desired Doneness: Continue roasting until the internal temperature reaches your preference. Insert the meat thermometer into the thickest part. Here’s a guide:
- Medium-Rare: 130-135°F (54-57°C)
- Medium: 135-145°F (57-63°C)
- Medium-Well: 145-155°F (63-68°C)
This will take roughly 30-45 minutes more, depending on size and your oven.
- Rest the Meat: This is the most important step! Transfer the lamb to a clean cutting board and tent it loosely with foil. Let it rest for a full 15-20 minutes. This allows the juices to redistribute, ensuring every slice is moist.
- Slice and Serve: Slice the lamb against the grain into thin strips. This makes it more tender to eat. Serve with the accumulated juices from the board.
Tips for the Best Results
- Don’t Skip the Rest: Cutting immediately will cause all the flavorful juices to run out onto the board.
- Use Fresh Herbs: They make a significant difference in flavor compared to dried for this paste.
- Check Temperature Early: Ovens vary, so start checking the internal temp a bit early to avoid overcooking.
- Carving: Slicing against the grain shortens the muscle fibers, making each piece easier to chew.
What to Serve With Your Roast Lamb
This lamb pairs beautifully with so many sides. Here are some classic ideas.
- Roasted potatoes, either crispy or soft and creamy
- Steamed or roasted green beans, asparagus, or broccolini
- A fresh, simple salad with a lemony vinaigrette
- Mint sauce or a yogurt-based sauce with cucumber
- Buttered peas or glazed carrots
Storing and Reheating Leftovers
Leftover lamb is a treat. Store cooled slices in an airtight container in the fridge for up to 3-4 days.
For reheating, avoid the microwave if you can. It can make the meat tough. Instead, warm slices gently in a covered skillet with a splash of broth or water over low heat. You can also use it cold in sandwiches or salads—it’s delicious.
Frequently Asked Questions (FAQ)
What does “butterflied” mean for lamb?
Butterflying means cutting a thick piece of meat so it opens up and lays flat. For a leg of lamb, the bone is removed and the meat is unfolded. This creates a more even thickness for faster, more uniform cooking.
Can I use dried herbs instead of fresh?
You can, but the flavor will be less vibrant. If using dried, reduce the amount by two-thirds. So, use about 1 tablespoon each of dried rosemary and thyme instead of 3 tablespoons fresh.
How long to cook butterflied leg of lamb per pound?
At the method described (starting high, then reducing to 350°F), plan for about 10-12 minutes per pound total cooking time to reach medium-rare. Always rely on your meat thermometer for accuracy, as oven temperatures can vary.
Why is my lamb tough?
Tough lamb is usually a result of overcooking. Lamb is best served at medium-rare to medium for optimal tenderness. Also, ensure you are slicing it against the grain, which is crucial for texture.
Can I marinate the lamb with the paste overnight?
Absolutely! Applying the paste and letting the lamb sit, covered, in the refrigerator overnight will deepen the flavors even more. Just remember to take it out an hour before roasting to come to room temperature.
This recipe is a reliable way to prepare a beautiful meal. The combination of garlic, rosemary, and thyme with the rich lamb is a classic for good reason. With these simple steps, you’ll have a tender, flavorful roast that feels both impressive and comforting. Give it a try for your next special dinner.