Roast Leg of Lamb : Tender, Juicy & Packed with Flavour
The roast lamb leg is a classic show-stopper for family gatherings and festive occasions. The secret to achieving tender and melt-in-the-mouth meat? Slow, gentle cooking.
By roasting at moderate temperature for several hours, the lamb develops deep flavour and remains incredibly juicy.
Oven-Roasted Leg of Lamb: A Tender and Flavourful Classic
A roasted leg of lamb is one of those classic dishes that never goes out of style.
Traditionally served for family gatherings and festive holidays like thanksgiving, Christmas or Easter, it’s the kind of meal that brings everyone to the table.
What truly makes it exceptional is the slow cooking method. Gentle heat over several hours allows the meat to develop rich flavour while becoming wonderfully tender.
For a 2.5 kg leg of lamb, plan about three hours in the oven at 180°C (fan-assisted).
This slow roast ensures the meat stays juicy and full of character.
With the right techniques, proper seasoning, steady heat, and a good resting time, you can achieve a melt-in-the-mouth texture every time.
Start by choosing a quality cut and seasoning it generously with garlic, rosemary, thyme, salt and pepper.
Roast at a moderate temperature, baste as it cooks, and let it rest before carving to keep the juices locked in.
Serve it with creamy mashed potatoes, roasted vegetables or your favourite sauce.
With this simple approach, your lamb will be tender, flavourful and truly impressive.
Why Cook Lamb Slowly?
Slow cooking gently breaks down the connective tissues, giving the lamb that incredibly tender, “fall-apart” texture. It also allows the flavours to deepen and the meat to stay juicy without drying out.
- 3 hours at 180°C (fan-assisted): Produces tender, flavourful meat with a classic roast texture.
- 4 hours at 160°C: Results in even softer, more delicate meat.
- 7 hours at 120°C: Creates ultra-tender lamb that literally falls off the bone.
How to Thaw a Frozen Leg of Lamb
If your lamb leg is frozen, it’s best to thaw it slowly in the refrigerator for safe, even defrosting. Allow about 7 hours of thawing time per 500 g.
As a guide:
- A 1.2 kg leg needs roughly 12 hours.
- A 2 kg leg needs about 24 hours.
- A 2.5 kg leg needs around 35 hours.
Once fully thawed, let the meat sit at room temperature for a short while before cooking. This helps it cook more evenly and improves the final texture.
Ingredients for Oven-Roasted Leg of Lamb
How much meat should you plan per person?
To make sure everyone has enough, count about 200-250 g of boneless meat per person. If you’re cooking for big eaters, it’s safer to allow a little more.
In my case, I cooked a 1.2 kg leg of lamb for 6 people, 2 adults and 3 children (aged 5 to 15). After a generous meal, we still had a bit left over, which shows this amount was perfectly adequate.
If you’re preparing a bone-in 1.2 kg leg, it will comfortably serve 4 hungry adults.
A 2.5 kg bone-in leg is ideal for 8 adults with good appetites.
Essential ingredients for a flavourful roasted leg of lamb
A delicious roast leg of lamb only requires a few simple, quality ingredients:
- A fresh leg of lamb
- Olive oil and a little butter for richness
- Fresh rosemary for its beautiful aroma
- A few garlic cloves to tuck under or into the meat for extra flavour
- Salt and pepper, nothing more
You can also add sliced onions, celery or carrots to create a vegetable bed for the lamb to rest on as it cooks.
If you like adding a little water to the roasting pan to create steam or to baste the meat once it mixes with the cooking juices, feel free to replace it with vegetable or lamb stock for even more depth of flavour.
Main Ingredients for the Best Oven-Roasted Leg of Lamb
- 1 leg of lamb (about 2.5 kg): Choose a fresh, good-quality cut with a nice layer of fat for tenderness and flavour.
- 4 garlic cloves: Used whole or sliced to infuse the meat with a deep, aromatic taste.
- 3 sprigs of fresh rosemary: A classic pairing with lamb, adding an earthy, fragrant note.
- Bay leaves: Enhance the flavour of the cooking juices and create a more aromatic roast.
- Thyme (fresh or dried): Complements rosemary and adds a subtle herbal depth.
- 50 g butter: Brushed over the meat for richness and a beautifully golden crust.
- 3 tablespoons olive oil: Helps the herbs and spices adhere to the lamb and promotes even browning.
- Fine salt & coarse salt: Fine salt for seasoning the meat thoroughly; coarse salt for finishing and extra texture.
- Freshly ground black pepper: Brings gentle heat and enhances all the other flavours.
- 2–3 onions, sliced into rings: Used as a flavourful bed under the meat, preventing it from sticking and enriching the sauce.
- 250 ml vegetable or lamb stock (optional): Adds moisture to the roasting pan and creates delicious, ready-made basting juices.
You can also layer onions, celery or carrots at the bottom of the roasting dish. This “vegetable bed” lifts the lamb slightly, helps it cook more evenly, and gives extra flavour to the juices. Add a splash of stock or water if needed to keep the environment moist during cooking.
Preparation & Roasting Steps for a Perfectly Tender Leg of Lamb
– Preparation
- Season the lamb: Rub the entire surface of the leg generously with fine salt to enhance flavour and help the meat absorb the seasoning.
- Add garlic aroma: Using a sharp knife, make small incisions in the lower part of the leg (the “souris” Or lamb shank). Tuck half or whole garlic cloves into the slits, depending on their size.
- Repeat on the other side: Make a few incisions on the opposite side as well, but avoid cutting too deeply so the juices stay inside the meat.
- Insert the rosemary: Slide sprigs of fresh rosemary into some of the cuts to infuse the lamb with its fragrant, earthy aroma.
- Prepare the roasting dish: Slice the onions into thick rings and arrange them in the bottom of the dish to form a flavourful bed. Add a few bay leaves, then place the lamb leg on top.
– Seasoning & Oiling
- Oil the meat: Drizzle the lamb generously with olive oil and massage it over the surface.
- Add herbs and spices: Sprinkle with chopped rosemary, thyme, coarse salt and freshly ground black pepper. Add another light drizzle of oil to help everything adhere.
- Enhance flavour: Scatter a few whole garlic cloves (left in their skins) around the meat for a mellow, caramelised garlic taste. Add a couple more bay leaves on top.
– Cooking
- Preheat the oven: Set your oven to 180°C (fan-assisted).
- Roast the lamb: Cook for roughly 30 minutes per 500 g for a juicy, slightly pink finish.
- Example: a 1.2 kg leg needs about 1 hour 15 minutes.
- Add moisture: After the first 30 minutes, pour half a glass of boiling water into the bottom of the dish to prevent the juices from burning.
- Top up if needed: If the pan dries out, add a splash of water or stock. Use small amounts so the meat doesn’t steam too much.
– Resting
- Baste and cover: Once cooked, remove the lamb from the oven and spoon some of the cooking juices over the top. Cover loosely with foil.
- Let it rest: Allow the meat to rest for at least 30 minutes before carving. This essential step lets the juices redistribute, resulting in tender, succulent slices.
Cooking Time for a Leg of Lamb (Fan-Assisted Oven at 180°C)
In a fan-assisted oven, the cooking time depends on the weight of the lamb and the level of doneness you prefer. Here is a simple guide:
- Rare / Pink: 25 minutes per 500 g
- Medium (classic roast, slightly pink): 30 minutes per 500 g
- Well done (very tender, fall-apart texture): 40 minutes per 500 g
Example: Weight vs time:
| Weight of the leg | Rare/Pink (25 min/500 g) | Medium (30 min/500 g) | Well done (40 min/500 g) |
|---|---|---|---|
| 1 kg | 50 min | 1 h | 1 h 20 min |
| 1,2 kg | 1 h | 1 h 15 min | 1 h 35 min |
| 1,5 kg | 1 h 15 min | 1 h 30 min | 2 h |
| 2 kg | 1 h 40 min | 2 h | 2 h 40 min |
| 2,5 kg | 2 h 05 min | 2 h 30 min | 3 h 20 min |
How to Tell if Your Leg of Lamb Is Properly Cooked
A meat thermometer is the most reliable way to check doneness and make sure your lamb is cooked exactly the way you like it.
If you don’t have one, you can use the traditional method: pierce the meat and check the colour of the juices. The colour will tell you how far along the cooking is:
- Red juice: the lamb is undercooked.
- Light pink juice: the lamb is medium (perfectly cooked and slightly pink).
- Clear juice: the lamb is well done.
Using a Meat Thermometer
If you have a digital meat thermometer, this is the best way to ensure the lamb is cooked to your preference without drying it out.
Insert the probe into the thickest part of the meat, avoiding the bone:
- Rare / Pink: 65-70°C
- Tender (soft and melt-in-the-mouth): 70-75°C
- Well done: 75-80°C
How to roast the leg of lamb in video
What to Serve with Tender, Slow-Roasted Leg of Lamb
A beautifully cooked leg of lamb deserves sides that complement its rich, fragrant flavour. Here are some delicious options:
- Garlic and olive oil mashed potatoes: A rustic, creamy potato mash infused with garlic, simple and absolutely irresistible.
- Classic mashed potatoes: Smooth, buttery and comforting, perfect for soaking up the lamb’s juices.
- Celeriac purée: A slightly sweet, earthy alternative that pairs wonderfully with roasted meats.
- Parsnip purée: Light, silky and subtly sweet.
- Parsnip and potato purée: A perfect balance of sweetness and creaminess.
All of these sides are excellent choices and make the lamb even more enjoyable.
Other roast dishes to try
- Roast Stuffed Turkey Recipe
- Juicy Oven-Roasted Chicken
- Slow oven-braised lamb shanks
- Oven-Baked Clementine Glazed Salmon
Oven-roasted leg of lamb, tender and melt-in-the-mouth meat
- Total Time: 2 hours 50 minutes
- Yield: 4 portions 1x
Description
The roast lamb leg is a classic show-stopper for family gatherings and festive occasions. The secret to achieving tender and melt-in-the-mouth meat? Slow, gentle cooking. By roasting at moderate temperature for several hours, the lamb develops deep flavour and remains incredibly juicy.
Ingredients
- 1 lamb leg (approx. 2.5 kg)
- 4 garlic cloves
- 3 sprigs of fresh rosemary
- Bay leaves
- Thyme (fresh or dried)
- 50 g butter
- 3 tablespoons olive oil
- Fine salt & coarse salt
- Black pepper (freshly ground)
- 2–3 onions (sliced into rings)
- 250 ml vegetable or lamb stock (optional)
Instructions
– Preparation
-
Rub the entire surface of the leg generously with fine salt to enhance flavour and help the meat absorb the seasoning.
-
Using a sharp knife, make small incisions in the lower part of the leg (the “souris”). Tuck half or whole garlic cloves into the slits, depending on their size.
-
Make a few incisions on the opposite side as well, but avoid cutting too deeply so the juices stay inside the meat.
-
Slide sprigs of fresh rosemary into some of the cuts to infuse the lamb with its fragrant, earthy aroma.
-
Slice the onions into thick rings and arrange them in the bottom of the dish to form a flavourful bed. Add a few bay leaves, then place the lamb leg on top.
– Seasoning & Oiling
-
Drizzle the lamb generously with olive oil and massage it over the surface.
-
Sprinkle with chopped rosemary, thyme, coarse salt and freshly ground black pepper. Add another light drizzle of oil to help everything adhere.
-
Scatter a few whole garlic cloves (left in their skins) around the meat for a mellow, caramelised garlic taste. Add a couple more bay leaves on top.
– Cooking
-
Set your oven to 180°C (fan-assisted).
-
Cook for roughly 30 minutes per 500 g for a juicy, slightly pink finish.
-
After the first 30 minutes, pour half a glass of boiling water into the bottom of the dish to prevent the juices from burning.
-
If the pan dries out, add a splash of water or stock. Use small amounts so the meat doesn’t steam too much.
– Resting
-
Once cooked, remove the lamb from the oven and spoon some of the cooking juices over the top. Cover loosely with foil.
-
Allow the meat to rest for at least 30 minutes before carving. This essential step lets the juices redistribute, resulting in tender, succulent slices.
- Prep Time: 20 min
- Cook Time: 2 hours 30 min
- Category: Oven-baked, roast, main dish
Nutrition
- Serving Size: 1 portion
- Calories: 195 kcal