How to Roast a Leg of Lamb (Bone-In or Boneless)
Timing charts by weight and doneness, bone-in vs boneless, and how to get a rosy pink centre with a crust.
A leg of lamb is the easiest impressive roast — one big muscle group, hard to ruin if you use a thermometer.
Bone-in or boneless?
| Bone-in | Boneless (butterflied or rolled) | |
|---|---|---|
| Flavour | Slightly better (bone + marrow) | Very good |
| Carving | Trickier around the bone | Easy, even slices |
| Cooking | A little slower, more even | Faster; butterflied is fastest of all |
| Stuffing | No | Yes — garlic, rosemary, anchovy, lemon |
| Feeds | 350–450g per person raw | 250–300g per person raw |
For a first roast, ask us to bone and roll the leg, or butterfly it for a 30-minute BBQ or oven cook.
The method (bone-in, ~2kg)
- Temper 1 hour out of the fridge.
- Stud and rub. Slit the surface, push in garlic slivers and rosemary. Rub with oil, salt, pepper.
- Sear the oven. 220°C for 20 minutes to build a crust.
- Drop to 180°C and roast to your target — pull it 3°C early and rest:
- Rare 52°C — ~15 min/500g at 180°C
- Medium-rare 56–58°C — ~18 min/500g
- Medium 62°C — ~22 min/500g
- Well done 70°C — ~28 min/500g
A 2kg leg to medium-rare: roughly 20 min sear + 70 min at 180°C. Always confirm with a thermometer in the thickest part, away from the bone.
- Rest 20 minutes, loosely tented. Make gravy from the tin while it rests.
Butterflied leg (fast)
Flat on a tray or over BBQ coals, skin/fat side to the heat first. 220°C or medium-high coals, ~15 minutes a side, target 56°C, rest 10. A marinade — garlic, lemon, oregano, oil — for a few hours first.
Per person & buying
Bone-in: 350–450g raw per person (a 2–2.5kg leg feeds 5–6). Boneless: 250–300g. See how much meat per person. All our lamb roasts are Australian grass-fed; bone, roll or butterfly on request.
Frequently asked questions
How long do you roast a leg of lamb?
After a 20-minute sear at 220°C, drop to 180°C: about 18 minutes per 500g for medium-rare (56–58°C), 22 min/500g for medium. A 2kg bone-in leg to medium-rare is roughly 90 minutes total. Always confirm with a thermometer and rest 20 minutes.
Bone-in or boneless leg of lamb — which is better?
Bone-in has slightly better flavour and stays a touch more even; boneless carves into clean slices, cooks faster, and can be stuffed. For an easy first roast, have the leg boned and rolled, or butterflied for a quick cook.
What temperature should roast lamb be?
52°C for rare, 56–58°C for medium-rare (the classic pink roast), 62°C for medium, 70°C for well done. Pull the roast 3°C below target — it climbs while resting.
How much leg of lamb per person?
Bone-in: 350–450g raw per person, so a 2–2.5kg leg feeds 5–6. Boneless: 250–300g per person. Buy slightly bigger for leftovers and more even cooking.