Discard the thick stems from the cilantro and wash them well. Make sure that you leave a little bit of the stem, because they have lots of flavor in them. Just remove the tough thick past of the stem. Drain it on a colander and keep it aside.

Heat the oil in a pan. Add the mustard seeds, Urad dal, red chilies and asafetida and fry it until the dal becomes golden brown.

Now add the washed cilantro and give it a quick stir. Turn off the flame right away. Do not fry/cook the cilantro because then it will lose its bright green color.

Cover the pan and leave it for 10 mins. The cilantro will wilt in the heat left in the pan and at the same time will remain green.

Grind the fried ingredients with the tamarind and salt. Be sure to leave a little bit of the fried seasoning (mustard seeds and urad dal) to add it to the thuvayal later.

Serve on top of hot rice with some gingelly oil or ghee. Also tastes great with dosai and idli.