Slow Roast Leg of Lamb

4.96 from 387 votes

Recipe video above. A very forgiving, very easy way to roast a leg of lamb, where the meat is slow-cooked until it's tender enough to pull it off the bone with tongs. It is not the blushing pink flesh carving sort (use this traditional Roast Lamb recipe if that's what you're after).

Lamb leg is lean, so to slow cook it's best to partially submerge in a flavoured liquid which keeps the flesh moist plus infuses with flavour. I'm using garlic and rosemary in this recipe - classic lamb flavours!

**IMPORTANT** Lamb leg is lean so it should only be cooked for 1.5 hours until blushing pink & juicy (per this traditional Roast Lamb recipe) or slow cooked for 4.5 hrs until fall apart (this recipe). Anything in between is tough and not nice! For more roast lamb recipes, browse the recipe collection or take my Roast Lamb Matchmaker to find your perfect recipe!

Prep Time15

Cook Time5 15

Total Time5 30

Course: Main

Cuisine: Western

Keyword: Roast Lamb Leg, Slow Roast Leg of Lamb

Servings: people

Calories: 605cal

Author: Nagi

Ingredients

2.25 kg / 4.5 lb leg of lamb , bone in (or shoulder) (Note 1)
1 1/2 tsp cooking salt / kosher salt (double for flakes)
1/2 tsp black pepper
1 1/2 tbsp olive oil
1 whole garlic head , unpeeled, cut in half horizontally
1 onion , quartered (unpeeled is fine)
2 rosemary sprigs (2 = whisper of rosemary flavour, 4 sprigs = stronger flavour)
3 cups beef stock/broth , low sodium (or homemade)
2 cups water

Gravy:

4 tbsp plain flour (all-purpose flour)
1 cup water
Salt and pepper , to taste

Cups - Metric

Instructions

ABBREVIATED

Season leg with salt and pepper, place upside down on garlic, onion and rosemary. Pour liquids in, drizzle with oil, cover with foil. Roast 4 1/2 hours at 170°C/335°F (150°C fan) until meat is pull-apart tender. Flip, return to oven 20 - 30 minutes at 200°C/390°F (180° fan) until well browned. Make gravy while resting.

FULL RECIPE

Preheat oven to 170°C/335°F (150°C fan-forced).
Place garlic, onion and rosemary in a metal roasting pan.
Season lamb: Place lamb leg right side up in the pan. (Note 2) Sprinkle the surface with half the salt and pepper and rub it in.
Turn lamb over and place it so it mostly sits on the garlic and onion. Sprinkle with remaining salt and pepper, rub it in. (Video helpful here)
Add liquids and cover: Drizzle lamb with olive oil. Pour broth and water around the lamb - it won't cover it, that's ok, the lamb sinks into it. Cover with foil (don't use a lid, you want a bit of liquid to steam out).
Slow roast: Place in the oven and roast for 4 1/2 hours. (See Notes for roasting time table)
Check meat: Remove from the oven, remove foil. Turn lamb over. Check it to ensure the meat is tender enough to pry a bit off easily with a fork. If not, return, covered, to oven.
Brown lamb: Return uncovered lamb to the oven and roast for a further 40 minutes or until well browned all over. (Don't increase the temperature as then it doesn't brown as evenly)
Rest: Remove lamb, spoon over pan juices generously. Transfer to serving platter, cover loosely with foil while you make the gravy (stays warm for 1 - 1 1/2 hours).

Gravy:

Skim fat: Use a large spoon to skim off and discard some of the fat from the surface of the liquid.
Add flour: Place pan on the stove on medium high. When the liquid bubbles, add flour. Use a whisk to mix it in - this may take a few minutes as the liquid reduces.
Add water: Once it looks like sludge (see video), whisk in 1/2 - 1 cup of water until it becomes a gravy consistency to your taste. Adjust salt and pepper to taste - I rarely add extra salt.
Strain gravy into a bowl, pressing juices out of the onion etc. Pour gravy into jug.

Serving:

The meat is tender so you will only need tongs to tear the meat off. Serve with gravy!

Notes

1. LAMB CUT: This recipe can be made with a leg or shoulder of lamb. Shoulder has more fat running through it than leg, so you can actually roast it uncovered (here's my Slow Roasted Lamb Shoulder recipe), but this recipe will also work with shoulder. This recipe is designed for lamb leg because it's leaner, so it benefits greatly from slow roasting partially submerged in liquid so it doesn't dry out. Cooking it this way also infuses it with flavour.

2. The upper side of the lamb leg has more meat so we want to roast that partially submerged in the liquid for most of the cooking time. The upper side of the lamb is rounder and usually has more fat. The underside has less fat and is more flat.

3. Essential side - Truly Crunchy Roast Potatoes!

4. More roast lamb recipes: Ultra Tender Slow Cooker Roast Lamb, Slow Roasted Lamb Shoulder, Classic Roast Lamb with Gravy (i.e. it's blushing pink inside) and Slow Roasted GREEK Leg of Lamb (delish lemon garlic flavours!).

5. Roasting Times (this cook method is pretty forgiving so round up to determine cook time eg if your lamb is 1.8kg, use the 2 kg cook times):

6. Gluten-free gravy - Skip the flour. Mix 2 1/2 tbsp cornflour/cornstarch with 3 tbsp water and use in place of the flour.

Servings - Allow ~350g/12 oz uncooked bone-in meat weight per person, so a 2.25kg /4.5 pound leg will serve ~6 people. I know this sounds like a lot of meat per person, but you lose more weight with slow cooked meats than roasting leg to blushing pink. plus the bone is sizeable and nobody can carve every scrap of meat off the bone. :)

Make-ahead - This is best served freshly made as leg is quite lean so it just isn't as succulent when reheated. It stays warm for 1 hour so you needn't worry about being 100% precise with cook timing. Leftovers will keep for 3 to 4 days in the fridge, or freezer for 3 months.

Nutrition per serving assuming 10 servings.

Nutrition - Calories in the nutrition are higher than actual because I do not know how to adjust for the fat that is skimmed off the liquid before making the gravy. I usually throw out about 1/3 cup which means the calories is probably closer to 500 calories per serving, and that's assuming all the gravy is consumed.

Nutrition