1) Soak the tamarind for 20 to 30 mins. Grind it and take thick concenterated juice about 500ml and keep it aside
2) Take a pan and add add 3 tbsp of oil and fry salt,curry leaves,black pepper,red chillies,urad dhal,toor dhal and hing.
3)Grind the above mixture to a coarse powder.
4) Take a kadai and add mustard seeds. Allow it spurt. Then add the thick concenterated tamarind juice. Allow it to boil.
5) Add the grinded powder to the tamarind juice and keep on stiring till it becomes a paste.