Thoroughly rinse the lentils and place in a pan with the water. Bring to the boil and add the turmeric and ginger. Cover and leave to simmer gently for 30mins.
Meanwhile, in a non-stick pan, fry the onion and garlic in the oil until nicely browned. Add the cumin seeds, coriander, and chilli powder and fry for a further 2mins. Set to one side until lentils are cooked.
Remove the lid and cook the lentils for a further 15-30mins till the water has all absorbed and the dhal is a thick as you like it. You need to stir frequently for the last 15mins as the lentils may stick to the pan. Once ready, remove the ginger, and stir in the onion and spice mix and the salt.