Clean, wash and add the dal to boiling water. Add turmeric, salt, half of the finely chopped ginger, garlic and cook on medium heat for 2-3 hours or pressure cook at 15psi for 1/2 hour. Uncover, cook further in same pan on low heat for 1/2 hour, stir and mash every now and then until a creamy consistency is achieved. Heat the ghee, add remaining ginger, stir, add sliced onions, chili, and fry until golden brown. Add cumin or coriander (optional). Pour over dal just before serving.