There’s nothing like a perfectly roasted boneless leg of lamb to bring everyone to the table! This simple recipe is loaded with flavor thanks to fresh rosemary, garlic, and a golden, crispy crust.
Whether you’re cooking for a holiday, a Sunday dinner, or just because, this lamb turns out juicy and tender every time. Plus, I’ll show you how to make a quick and delicious pan gravy from the drippings – because every great roast deserves a great sauce!
Check below for how to roast lamb, cooking times and temps as well as step by step instructions and photos.
Looking for another dinner recipe? Try my Herb Crusted Prime Rib, or my Crockpot Ham (with Oven Instructions)
Step-by-step photos and instructions are below!
This lamb recipe is the my go-to! I love the combination of rosemary and garlic for lamb, and the aside from it flavoring the meat from the inside out, the smell of it cooking is divine!
If you’ve ever been nervous to cook lamb, have never cooked lamb before, don’t worry, I got you!
I grew up in New Zealand – 3 million people, 20 million sheep – so lamb was always on the table! For me, it brings back memories. The smell of roast lamb in the oven takes me straight to Sunday dinners at home. Although we had lamb often, we always had it for Easter and special occasions!
What you’ll find in this post:
Lamb Cooking Temperature Guide
Use this as a guideline
| Doneness | Internal Temp F° | Internal Temp C° | Notes |
|---|---|---|---|
| Rare | 120-125°F | 49-52°C | Very pink, soft texture |
| Medium-Rare | 130-135°F | 54-57°C | Warm red center, tender and juicy (optimal for lamb) |
| Medium | 140-145°F | 60-63°C | Slightly pink center, firmer texture |
| Medium-Well | 150-155°F | 65-68°C | Mostly brown, less juicy |
| Well-Done | 160°F+ | 71°C+ | Fully brown, firmer, drier texture. Don’t do it. |
Always use a meat thermometer to check doneness. Insert it into the thickest part of the lamb. The lamb’s internal temp will rise about 5-10°F while resting.
Remove it a few degrees early to avoid overcooking. Rest the lamb for 10-15 minutes before slicing to lock in the juices.
Why you’ll love this recipe:
- Easy prep. Just a few ingredients and simple seasoning.
- Perfect for special occasions. Great for Sunday dinners, holidays, or impressing guests.
- Customizable doneness. Cook it to your preferred temperature.
- Pan gravy included. A rich, flavorful sauce made from drippings.
Frequently Asked Questions
How do I know when my lamb is done?
I recommend using a digital meat thermometer. Insert it into the thickest part of the lamb.
Can I cook this in a slow cooker?
Yes, but it won’t have the same crispy exterior and might overcook unless you keep a close eye on the internal temperature.
Can I use a bone-in leg of lamb?
Of course. Just adjust the cook time to about 20 minutes per pound and use a thermometer to check doneness.
What to serve with Roast Lamb
You can’t go wrong with potatoes of any kind. Grab some mashed potatoes to soak up the gravy, (or make au gratin potatoes). Roasted potatoes go well, too! Make some glazed carrots, and some green beans and we’re onto a winner!
Dinner rolls: try homemade Hawaiian rolls, 30 minute dinner rolls, or opt for my whole wheat rolls.
I serve my lamb with mint sauce, or mint jelly as well. You can make your own, or grab it from the condiment aisle of the grocery store.
I have included step-by-step photos and instructions, as well as tips and tricks in the post. If you’d rather skip all that, scoot right on down to the full recipe card located at the bottom of the post.
Key Recipe Ingredients
The full list of ingredients and amounts is found in the printable recipe card below.
- Boneless leg of lamb. Juicy and flavorful, but you could use bone-in lamb roast if preferred (adjust cook time). I buy my lamb at Sam’s Club or Costco.
- Fresh rosemary. Classic with lamb, but thyme or oregano can be used.
- Garlic cloves. Enhances the flavor – use fresh for the best taste. You can sprinkle garlic powder with the salt and pepper otherwise.
- Salt & pepper. Essential for seasoning.
- Olive oil. Helps create that beautiful crust. Any neutral oil can be used.
How to cook Boneless Leg of Lamb
Scroll for Recipe
This next part is only a photo tutorial of the recipe steps. The full list of ingredients, quantities and instructions can be found in the printable recipe card below.
Get prepped
Preheat the oven to 450 degrees F. Cut the rosemary into springs, and slice the garlic into thick slivers.
Pat the lamb dry with paper towels. Brush olive oil over the lamb. Make deep cuts into the top of the lamb.
Insert the garlic slices and rosemary into each slit, as deep as possible.
Season the lamb generously with salt and pepper.
Roast the lamb
Place the lamb in a roasting pan. Transfer to the preheated oven and roast for 30 minutes, then reduce the oven temperature to 350 degrees F.
Continue roasting for about 15-20 minutes per pound. A 4-pound roast will take about 60 minutes.
Rest and serve
Remove the lamb from the oven, remove the netting or kitchen twine and tent with foil. Let the lamb rest for 10 minutes before carving.
How to Make a Pan Gravy
Remove all but 2 tablespoons of drippings from the roasting pan. Place the pan on the stove over medium-high heat. Whisk in 2 tablespoons flour, cooking for about a minute. Slowly whisk in hot stock, stirring constantly until thickened. Season with salt, pepper, and fresh or dried rosemary.
Kylee’s Notes
- Let the lamb come to room temperature before roasting for even cooking. Take the lamb out of the refrigerator about 30-40 minutes prior to cooking.
- Use a roasting rack for better airflow and even browning.
How to store leftovers
Refrigerator
Store leftovers in an airtight container in the fridge for up to 3 days.
Freezing
For longer storage, freeze slices in a freezer-safe bag for up to 3 months.
Reheating
Reheat gently in the oven at 300 degrees F until warmed through, or use a skillet with a little broth to keep it from drying out.
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Boneless Leg of Lamb Recipe
Ingredients
Directions
Get prepped
- Pat the lamb dry with paper towels to remove excess moisture. This helps create a crispy golden crust when roasting.
- Brush the lamb with olive oil making sure to coat all sides evenly
- Use a sharp knife to make deep cuts about an inch into the top of the lamb. These will hold the rosemary and garlic, infusing the meat with flavor.
Assemble the roast
- Push the garlic slivers and rosemary pieces deep into the cuts you made making sure they go at least an inch into the meat so the flavors spread throughout. Some of the rosemary and garlic will stick out, but the deeper they go, the more flavorful the lamb will be.
- Generously season the lamb with salt & pepper rubbing it all over the surface.
Roast the lamb
- Preheat your oven to 450° F.
- Place the lamb in a roasting pan and transfer it to the oven. Roast for 30 minutes at this high temperature to create a flavorful crust.
- Reduce the oven temperature to 350° F.
- Continue roasting for about 15-20 minutes per pound. For a 4-pound roast. This will take a further 40 minutes, making around 60 minutes total. Use a meat thermometer to check doneness:
Rest & serve
- Remove the lamb from the oven and loosely tent it with foil.
- Let it rest for 10 minutes before carving to allow the juices to redistribute.
- Slice and devour
How to Make a Pan Gravy
- Remove all but 2 tablespoons of drippings from the roasting pan.
- Place the pan on the stove over medium-high heat.
- Whisk in 2 tablespoons flour, cooking for about a minute to remove the raw flour taste.
- Slowly whisk in hot stock, stirring constantly until thickened.
- Season with salt and pepper
Notes
Lamb Temperature
- Medium-rare: 130°F (recommended)
- Medium: 140-145°F
- Well-done: 160°F
Nutrition Facts
Disclaimer
Nutritional information is an estimate and provided to you as a courtesy. You should calculate the nutritional information with the actual ingredients used in your recipe using your preferred nutrition calculator.
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