Soak tamarind in hot water for for 30 mins.
Take a small pressure cooker.
Dry roast the mochai till the skin starts turning brown, till nice aroma rises. (If you want to soak and make, soak overnight).
Add 2 cups water. Pressure cook for 4-5 whistles, keep aside.
Extract tamarind juice from tamarind, Total 2 cups tamarind juice.
Peel garlic, onion and if you want to chop, chop it or you can add whole also (both).
Heat kadai with oil and temper it with the items given under the To Temper table.
Add the curry leaves,followed by garlic and fry for a minute and then add onion and fry till golden brown.
Then add the tamarind extract, turmeric, sambar powder, salt, Kashmiri chilli powder (if desired) and bring it to boil.
Add the pressure cooked Mochai kottai and along with the water and allow it to boil for atleast 12-15 mins. (Add water if necessary).
When the kuzhambu gets thick enough and the mochai gets well cooked in it,transfer to the serving bowl.