1. Soak the tamarind in 1 cup of water and extract the juice.
2. Heat the oil and roast all the ingredients from coriander seeds to red chillies.
3. Add kopra and roast lightly.
4. Grind all these with ginger to a smooth paste.
5. Mix the paste with tamarind juice.
6. Add about 6 cups of water, salt and jaggery.
7. Boil and simmer for 5 minutes and remove from fire.
8. Heat the oil or ghee for seasoning. Add mustard.
9. When it splutters, add curry leaves and onion.
10. Fry till onion is light brown and add to the saaru. Serve hot.

Yields:About 1 ½ Litre