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. 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

Add liquids and cover: Drizzle lamb with olive oil. Pour broth and water around the lamb. Cover with foil

Slow roast: Place in the oven and roast for 4.5 hours

Check meat: Remove from the oven, remove foil. Turn lamb over. Check it

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

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

Add water: Whisk in ½ - 1 cup of water until it becomes a gravy consistency to your taste

Strain gravy into a bowl, pressing juices out of the onion etc. Pour gravy into jug

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