Chop the tomatoes and keep it ready. In a heavy bottom pan, heat 3 TBSP of oil and add the chopped tomatoes along with turmeric powder. Mix well and let it cook covered until the tomatoes are mushy.
By now you will notice that most of the moisture has dried out as well. Depending on the kind of tomatoes, it might take less or more time for the tomatoes to dry up. During the last 10 minutes of the cooking time, add the tamarind piece to allow it soften.
Turn off the flame and let the mixture cool to room temperature.
Once the tomato mixture cools down, grind it into a paste. Make it as smooth as you like or you could leave it a little bit of the coarse side. I ground it pretty smooth.
In the meantime, roast ½ TBSP of mustard seeds and ½ TBSP of fenugreek seeds until golden brown and aromatic.
Let it cool down and then grind it to a smooth powder.
In the same pan, heat ¼ cup of oil and add 1 tsp of mustard seed. Once the seeds crackle, add the peeled garlic pods and fry it for 30 seconds or until slightly softened.
Now add the chili powder and asafetida to the hot oil and give it a quick stir.
Add the ground tomato paste and mix well. Now add the salt needed and mix well until the oil oozes out (about 5 to 7 minutes).
Add the fenugreek and mustard powder mixture and mix well.
Turn off the flame and let the pickle cool down before transferring to a container. Store it in the refrigerator for longer shelf life.