How do I roast a leg of lamb so it is pink in the middle?

The temperatures that give rare, pink and well-done lamb, why a leg is thicker at one end on purpose, and the resting that decides whether it is juicy.

Difficulty: intermediate
Time: 25 min
Read: 4 min

Short answer

Roast at 200°C for 20 minutes to colour, then 170–180°C until the thickest part reaches about 52–54°C for rare, 57–60°C for pink, 65–68°C for well done. Pull it 3–5°C below your target because it keeps cooking. Rest 20–30 minutes, then carve across the grain.

A leg of lamb is a big, tapering, bone-in joint, which means it will never cook evenly and does not need to. The thin shank end reaching medium while the thick end is still pink is the design, not a fault — it lets you serve a table where people want different things from the same joint.

What you'll need

Bone-in leg of lamb
A probe thermometer
A roasting tin and a rack or bed of vegetables
Garlic, rosemary, anchovy if you like it

Step by step

Salt it early and take it out of the fridge in good time.Salt the leg generously several hours ahead if you can, or the night before. A joint this size takes a while to lose its fridge chill; 45–60 minutes out is useful, though it matters much less than people think and is not a substitute for a probe.
Stud it and season the fat.Cut small slits through the fat into the meat and push in garlic slivers and rosemary tips. A sliver of anchovy in each slit is a classic that does not taste of fish in the finished meat. Rub the outside with oil, salt and pepper.
Start hot, then drop the temperature.20 minutes at 200–220°C to set colour on the fat, then down to 170–180°C for the rest. High heat throughout overcooks the outer layer badly on a joint this thick; the two-stage approach gives you colour without a wide band of grey.
Probe the thickest part, avoiding the bone.Push the probe into the deepest muscle from the side, checking that the tip is not touching bone — bone conducts heat differently and reads high. Take several readings and trust the lowest. Roughly: 52–54°C rare, 57–60°C pink or medium, 65–68°C well done, all measured before resting.
Pull it early for carryover.A leg of lamb will climb another 3–5°C after it leaves the oven, more for a very large one. Take it out below your target, not at it. This single habit is the difference between pink lamb and disappointed lamb.
Rest it properly.20–30 minutes, loosely tented with foil, somewhere warm but not in the oven. A joint this size holds heat easily for that long and will still be hot on the plate. Use the time for gravy, potatoes and the green vegetables.
Carve across the grain, working around the bone.Sit the leg with the bone running left to right. Cut down to the bone at intervals, then run the knife along the bone to release the slices. Turn it over and take the rest off the underside. Slices should be across the fibres, not along them.

Tips

A butterflied leg — boned and opened flat — cooks in a third of the time and is far easier on a barbecue, at the cost of the presentation and the bone in the gravy.
Lamb fat sets quickly and tastes waxy when cold, so serve lamb on warm plates. It matters more with lamb than with beef.
If half the table wants it well done, carve from the thin shank end first — it will already be several degrees further on than the middle.
The pan juices under a lamb leg are strong and slightly sweet. Skim the fat aggressively before making gravy or it will be greasy.

Common mistakes

Roasting to a time chart with no probe — Legs vary in shape as much as in weight, and a wide short leg and a long thin one of the same weight cook differently. The chart gets you to the ballpark; only a probe gets you to the plate.
Taking it out at your target temperature — Carryover takes it past. Pink becomes medium, medium becomes grey. Pull low.
Resting it in a switched-off oven — A warm oven keeps adding heat, so carryover overshoots badly. Rest on the worktop, loosely covered.

Questions people ask

Is pink lamb safe?

For a whole, intact leg, yes. Contamination on whole muscle is a surface phenomenon and roasting destroys it on every exposed surface. The exception is a boned and rolled leg, where the outside surface has been rolled inside — that should be cooked thoroughly throughout.

How long per kilo should I roast a leg of lamb?

As a starting estimate at 180°C, roughly 20 minutes per kilo for rare, 25 for pink and 30 for well done, plus about 20 minutes overall. Treat that as a way of deciding when to start probing rather than as an answer.

Bone-in or boned and rolled?

Bone-in tastes better, stays juicier and gives you a bone for stock, but is harder to carve. Boned and rolled carves into neat rounds and takes stuffing, but must be cooked through rather than served rare because rolling moves the outer surface inside.