Take a pan, heat oil and add tomatoes.
Saute for a minute making sure is oil is coated well to all the peices.
Cover and simmer for 10 minutes until the tomatoes have cooked completely turning soft.
Add tamarind extract and mix well.
Cover and simmer for 10 more minutes.
The mixture should turn thick, sauté till oil is released from sides.
Ground the fenugreek seeds and mustard seeds into powder. Set aside.
Add methi-mustard powder, turmeric, chilli powder, salt and jaggery.
Saute on low flame till the spices gets cooked well.
In another pan, for tempering, add oil, mustard seeds, asafoetida, garlic cloves, red chilli and curry leaves.
Saute for 2 min and pour tempering over tomato mixture and mix well.
Serve tomato pickle along with rice, idli or dosa.