Mor Kuzhambu - Curd gravy

Sour Curd - 1 cup
Tamarind - 1/2 sp (Opt)
Turmeric - a pinch

To soak and grind:
Tur Dal - 1/2 sp
Gram Dal (Opt)- 1/4 sp
Dhaniya - 1/2 Sp
Cumin - 1/2 sp
Red Chilli - 1
Green Chilli -1
Ginger - 1 small piece
Coconut - 1 sp

Beat curd well. Add salt and pinch of turmeric to it.
Soak for half hour and grind to paste the mentioned ingredients.
Mix the grounded mixture to curd.
Cook just a couple of minutes /till it boils up. Switch off

-- If the curd is not sour, add 1/2 sp of tamarind to it.