Soak lemon-sized tamarind in 1 cup of water for atleast 20 mins. Squeeze well and discard the pulp. In a small tadka pan, fry the sundakkai vathal(sun dried turkey berry) till it puffs up. Drain the oil and keep the fried sundakkai aside.
In a pan, add Gingelly oil/ Nallennai. Now add mustard seeds, fenugreek seeds for tempering. Let mustard crackle.
Now add curry leaves and Dry Red chillies.
Add chopped shallots and garlic. Cook till shallots turn soft.
Now add turmeric powder, sambar powder and salt. If you do not have sambar powder, add 1 tsp of Red Chilli powder and 2 tsp of coriander powder. fry for few seconds
Its time to add tamarind extract. Make sure the kulambu is watery now. If not, add 1/2 cup of water to make it watery.
Let it simmer for 15 mins in low flame. After 15 mins, you will be able to see the oil floating.
Now add fried sundakkai vathal and a small piece of Jaggery. Let it simmer for 2 mins.
Switch off the flame. Serve with steamed Rice along with appalam(papad).