Ingredients

CupsMetric

2.25 kg / 4.5 lb leg of lamb , bone in (or shoulder) (Note 1)
Salt and pepper
1.5 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

Instructions

Preheat oven to 170°C/335°F (standard) or 150°C (fan).
Place garlic, onion and rosemary in a metal roasting pan.
Season lamb: Place lamb leg right side up in the pan. (Note 2) Sprinkle generously with salt and pepper and rub it in.
Turn lamb over and place it so it mostly sits on the garlic and onion. Sprinkle with more 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 4.5 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 oven for a further 45 minutes or until well browned.
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 – 1.5 hours).

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.