Roast Leg of Lamb with Blackened Honey Dijon Crust

Why You’ll Love This Recipe

I like this recipe because it delivers restaurant-level results with simple ingredients and straightforward steps. The honey Dijon crust blackens beautifully in the oven, giving the lamb a crisp, caramelized exterior while locking in moisture. Garlic tucked into the meat adds flavor throughout, and the roasted vegetables beneath catch all those delicious juices. It’s a dish that looks impressive but is surprisingly easy to execute.

Ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

For the lamb:
5-pound bone-in leg of lamb
2 cloves garlic, thinly sliced (for inserting into lamb)

For the honey Dijon garlic rub:
10 cloves garlic
1 tablespoon dried oregano
1 tablespoon dried thyme
1 teaspoon dried rosemary
1½ tablespoons kosher salt
2 teaspoons black pepper
1/4 cup honey Dijon mustard
1 tablespoon olive oil

For the roasting pan:
4 cloves garlic, smashed
2 medium red onions, thinly sliced
10–11 whole carrots, peeled
2 tablespoons olive oil
2 teaspoons kosher salt
1/2 teaspoon black pepper

For the onion gravy:
1/4 cup flour
2 tablespoons honey Dijon mustard
1/2 cup white cooking wine (or chicken broth)
3 cups chicken broth
Salt and pepper, to taste

Directions

1. I take the lamb out of the fridge and let it come to room temperature while prepping everything else.

2. I slice two cloves of garlic and make 1-inch deep cuts all over the lamb, inserting a slice of garlic into each cut.

3. For the rub, I blend 10 garlic cloves, oregano, thyme, rosemary, salt, pepper, honey Dijon mustard, and olive oil until it forms a thick paste.

4. I rub the mixture all over the lamb, pressing it into the surface.

5. I prep the vegetables by spreading sliced red onions, smashed garlic, and whole carrots on the bottom of a roasting pan. I drizzle with olive oil and season with salt and pepper.

6. I place a roasting rack over the vegetables and set the lamb on top.

7. I let the rubbed lamb sit at room temp for 15 minutes (or up to an hour) while preheating the oven to 500°F. I make sure the oven is screaming hot before roasting.

8. I insert a meat thermometer into the thickest part of the lamb, making sure it doesn’t touch the bone.

9. I roast the lamb at 500°F for 10 minutes, then lower the oven to 400°F without opening the door.

10. I continue roasting for 1 hour and 10 to 25 minutes, depending on my desired doneness (I prefer medium—see temperature guide below).

11. I remove the lamb from the oven and cover it loosely with foil to rest for 20 minutes.

12. I remove the carrots to a platter and leave the onions in the pan for the gravy.

To make the onion gravy:

1. I drain excess fat from the pan, keeping about 2 tablespoons (or adding olive oil if needed).

2. I place the roasting pan over two burners on medium heat.

3. I stir in the flour and cook for a minute, then add the honey Dijon mustard and stir again.

4. I deglaze with the white wine (or broth), scraping the pan, and simmer for 2–3 minutes.

5. I slowly stir in chicken broth, letting it thicken to a smooth gravy. I season with salt and pepper to taste.

6. I strain or pour into a gravy boat to serve.

To carve the lamb:
I remove any twine, slice parallel to the bone first, then turn and slice perpendicular, cutting down to the bone. I finish by slicing along the bone to release the pieces.

Servings and timing

This recipe serves 8 and takes about 1 hour and 45 minutes total, including 20 minutes of prep and 1 hour 25 minutes of cook time.

Variations

• Use lamb shoulder: If I want a more budget-friendly cut, I sometimes use bone-in lamb shoulder with similar seasoning.

• Fresh herbs: When I have them on hand, I swap dried herbs for fresh for a brighter flavor.

• Garlic herb butter finish: After roasting, I sometimes brush the sliced lamb with garlic butter before serving.

• No wine? I use extra chicken broth with a splash of lemon juice to replace white wine in the gravy.

• Add potatoes: I’ll sometimes add halved baby potatoes to the roasting pan for a complete one-pan meal.

Storage/Reheating

I store leftover lamb slices in an airtight container in the fridge for up to 4 days. To reheat, I warm the slices gently in the oven with a splash of broth to keep them moist. The onion gravy also keeps well for up to 4 days and can be reheated on the stove.

FAQs

What internal temperature should I cook the lamb to?

I use this guide for doneness (keep in mind it rises 5°F while resting):

• Rare: 115–120°F

• Medium-rare: 120–125°F

• Medium: 130–135°F

• Medium-well: 140–145°F

• Well-done: 150–155°F

Do I have to use a bone-in leg of lamb?

No, boneless works too—I adjust the cook time slightly (it usually cooks a bit faster). I just make sure to secure it with kitchen twine to hold its shape.

Can I prepare this ahead of time?

Yes. I often rub the lamb and prep the veggies a day ahead, then store everything in the fridge. I let it sit at room temp for an hour before roasting.

What’s the best way to slice the lamb?

I use a long, sharp slicing knife and cut against the grain for the most tender pieces. Starting parallel to the bone helps carve neat slices.

Can I skip the gravy?

Sure, but I don’t recommend it. The onion gravy is packed with flavor from the lamb drippings and adds so much richness to the final dish.

Conclusion

This Roast Leg of Lamb with Blackened Honey Dijon Crust is my go-to for a showstopping main dish that’s full of bold flavor and beautiful texture. The crust is perfectly caramelized, the meat stays juicy, and the onion gravy brings it all together. Whether I’m hosting a holiday or just want a hearty Sunday dinner, this lamb roast always impresses—and it’s easier than it looks.

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