Heat a pan with ghee. Saute it with mustard seeds. Once they splutter add the curry leaves and green chillies and stir. Now add the chopped mango and tomato pieces to it and fry in medium flame for 1 minute.
Pour the tamarind juice and add salt, turmeric powder and hing powder. Once they boil well and raw smell of tamarind goes add the powder and mix well.
Dilute the boiled dal with a cup of water and pour into the boiling rasam. Switch off the stove after a minute. Garnish with coriander leaves.