- 1Bring to room tempTake the leg out of the fridge 60 minutes before roasting. A cold-centre lamb roasts unevenly — the outside is done before the middle even warms up.
- 2Preheat and prepPreheat the oven to 220°C fan-forced. Score the fat cap on top of the leg in a diamond pattern, cutting just into the fat but not the meat. This lets the fat render and lets seasoning penetrate.
- 3Stud with garlic and rosemaryUse a sharp paring knife to make deep 2cm slits all over the top and sides of the leg. Push a garlic sliver and 2-3 rosemary leaves into each slit — aim for about 20-25 studs total. Rub the whole leg with olive oil, then season heavily with salt and pepper.
- 4Prepare the trayToss the carrots, red onion wedges, potatoes and halved garlic head in a large roasting tray with 1 tbsp olive oil, salt and pepper. Nest the lamb on top of the vegetables — they'll catch the juices and crisp up beautifully.
- 5Blast the ovenRoast at 220°C for 20 minutes to develop a dark crust and start the vegetables. Then reduce the oven to 180°C fan-forced.
- 6Add the liquidPour the wine and stock into the tray around the lamb (not over the crust). This creates gravy while the meat cooks and stops the vegetables burning.
- 7Roast to temperatureContinue roasting for 55-70 minutes for medium-rare (57°C internal), 75-90 minutes for medium (63°C internal). Use a digital thermometer — timing alone is unreliable on a boneless leg. Baste every 20 minutes with pan juices.
- 8Rest properlyMove the lamb to a carving board and tent loosely with foil. Rest for 15-20 minutes — this is non-negotiable. The internal temperature will climb 3-4°C during rest, and the fibres relax so the juices don't run out when you carve.
- 9Make the gravyMeanwhile, place the roasting tray on the stove over medium-high heat. Mash the roasted garlic head into the pan juices. Simmer to reduce to a spoonable gravy consistency, about 5 minutes. Strain if you want silky, leave rustic if you want the roasted-vegetable pieces.
- 10Carve and serveSlice the lamb across the grain into 1 cm ribbons. Plate with the roasted vegetables, spoon the gravy over generously, and serve with fresh mint sauce on the side. A cold WA rosé cuts the richness perfectly.
There's a specific atmosphere to a Perth Sunday afternoon in autumn — the kids in the garden, the football on TV somewhere, a cold rosé in the fridge, and the smell of a lamb leg roasting through the whole house. This recipe is the one our head butcher's family cooks every second Sunday. It's dead simple, feeds six, and produces the kind of leftovers that make Monday's sandwich the best meal of the week.
Australian lamb is the country's quiet culinary superpower — grass-fed, well-priced compared to any European lamb, and consistently better than the equivalent supermarket product from a proper butcher. THE BUTCHER BOX sources our lamb from South Australian and WA family farms with a preference for spring-lamb harvests. Every leg is butcher-tied, halal certified, and delivered fresh across Perth every Friday.
Bone-in vs boneless leg — pick your fight
Both work, but the technique below is written for a boneless leg because it's simpler to portion, easier to carve at the table, and roasts more evenly:
- Boneless leg — carve into ribbons across the grain. Easier for guests. Slightly faster cook.
- Bone-in leg — more flavour, more visual impact, but you'll need to carve around the bone (rewarding, but harder for a beginner). Add 15-20 minutes to the cook time.
If you're new to roasting, start with boneless. Upgrade to bone-in once you've done this recipe twice.
Why studding matters
Cutting deep slits into the leg and pushing garlic + rosemary in isn't cosmetic — it's functional. As the lamb cooks, the garlic softens and infuses the meat from the inside out. The rosemary aromatics travel through the muscle fibres via the fat that renders during the roast. Skip this step and you get a lamb that's flavoured only on the surface. Do it properly and the flavour is layered all the way through.
The right oven temperature strategy
Two-stage roasting:
- 220°C for 20 minutes — high heat to develop a dark, crusty exterior via the Maillard reaction. This is where the flavour is.
- 180°C for the rest — moderate heat to cook the interior gently to your target temperature.
If you roast at 220°C the whole way, the outside burns before the inside is ready. If you roast at 180°C the whole way, you miss the crust. Two-stage is the technique every proper Sunday-lunch cook uses.
Doneness — get a thermometer
Timing alone lies. Two lambs the same weight can differ by 15 minutes depending on how cold-centred they were before going in the oven, how efficient your oven is, and how much fat is on the surface. A digital probe thermometer removes the guessing:
- 57°C — medium-rare (blush of pink through the middle) — the sweet spot for most Perth cooks
- 63°C — medium (light pink) — a family compromise if there are kids
- 68°C — well done (grey but not chewy) — only if you must
Do NOT overcook. Lamb tastes best at medium-rare to medium. Well-done lamb loses everything that makes it worth $19/kg.
Sides that don't compete
The lamb is the hero. Keep the sides simple:
- Roasted root vegetables in the pan alongside — they catch the juices and self-caramelise
- Steamed green beans with lemon and sea salt
- A green salad with a sharp mustard vinaigrette
- Yorkshire puddings if you have the oven space (bake in the last 15 minutes, high heat)
- Fresh mint sauce on the side — never gravy AND mint together; pick one per bite
Wine
A good rosé cuts the richness — a Margaret River rosé is the classic Perth pick. If you're going red, a light Pinot Noir (Willow Bridge, Xanadu) is perfect. Skip anything heavy and tannic — you'll clash with the lamb's delicate flavour.
Leftovers — the sandwich rule
This is where the recipe gives twice. Wrap the leftover roast lamb tightly and refrigerate. Two Monday-lunch options:
- The classic: sliced cold lamb on sourdough with mustard, watercress and a slice of tomato. That's it.
- The kebab: chop the lamb, fold into warm Turkish bread with tzatziki, tomato, red onion, mint and chilli. Better than any takeaway in Northbridge.
Or freeze the leftover meat sliced (portion into flat freezer bags) for a lamb curry in a fortnight — thaw, sauté with onion, garlic, curry powder, tomato paste and coconut milk, and dinner's on the table in 25 minutes.
Where to source the leg
Every Friday, we deliver Australian boneless lamb legs across Perth metro. Order by Wednesday 7pm. Available:
- À la carte on the lamb page
- On the Family Feast Box as a rotating hero cut
- Custom size on request — leave a note at checkout and we'll butcher-tie to your target weight
The Sunday roast is a Perth tradition worth keeping. Set aside three hours, invite family over, pour a good rosé, and let the oven do the work. By dinner your house smells like every childhood Sunday you can remember.
