Grind all the spices with a mortar and pestle.
Add the olive oil, lemon juice and garlic and mix to form a paste.
Using a small sharp-pointed knife, make small incisions all over the leg of lamb and rub the paste into the meat.
Place the leg in a large freezer bag and marinate in the fridge for at least four hours and preferably overnight.
Preheat the oven to 160 °C.
Remove the leg from the fridge and leave to reach room temperature.
Place the meat in a roasting pan, season with salt and pepper and roast for about one hour until brown on the outside but still pink inside.
Rest for 15 to 30 minutes before carving into thin slices.
Garnish with fresh coriander and serve at room temperature with chimichurri,
Mix 30 ml white wine vinegar, 50 ml olive oil, 45 ml chopped Italian parsley, 5 ml oregano, 2 crushed garlic cloves, 5 ml paprika and 1 green chilli.