Soak the dal for 2 hours in plenty of water. Drain and boil in fresh water until tender but not overcooked. Drain and set aside.
Heat the oil in a large frying pan over medium high heat. Add the lamb and fry until well browned. Add the ginger, garlic, turmeric, chilli powder, garam masala, onion and tomato. Reduce heat to medium low and simmer until the oil separates from the mixture.
Add salt, sugar, yoghurt and water. Simmer over low heat until the lamb is tender.
Add the dal and bring the mixture to the boil. Lower the heat to medium and simmer until mixture is well blended.
Garnish with coriander before serving with basmati rice or naan.