Preheat the oven to 160 degrees Celsius.
In a baking pan put some olive oil and place a roughly chopped onion and some rosemary.
Make 10 small incisions in the lamb leg and push in the garlic cloves and some rosemary.
Massage the leg with some olive oil, salt, cumin, black pepper and ginger. Place it on the onions in the baking pan. Put some aluminium foil over the leg and put it in the oven.
Cook for at least 5 hours until the leg is completely tender and you can shred it easily with a fork.