Add the moong dal, coconut milk and turmeric to a pan. Pour over 2 cups of water. Bring to a boil then reduce the heat to very low so that it's very gently bubbling.Cover and cook for 35 minutes until the dal is soft and creamy, then remove from the heat.NOTE: you will most likely need to add more water during the cooking if the dal becomes too thick. The consistency should be similar to a creamy soup, so adjust accordingly. (See video recipe for a guide.)
Using a wok or deep frying pan over a moderate heat, add the ghee an let it get hot.Add the cumin seeds, mustard seeds and dried chillies and let them sizzle for 20 seconds.Add the curry leaves and let them splutter briefly before adding the shallots, followed by the green chilli, chilli powder, salt and then finally tomato. Stir and reduce the heat to low - let this all sizzle for 1 minute, stirring constantly.Remove from the heat.
Tip the tadka into the dal (reserve a little for garnish) and stir in well.
When you're ready to serve, heat the tadka until it starts to sizzle again and then pour ot over a serving bowl of hot dal. Sprinkle with fresh cilantro if you like.
