To begin, dry roast mustard seeds, fenugreek seeds, chana dal, and coriander seeds until aromatic. Cool, grind into a fine powder, and keep aside.

Heat oil in a pan. Add the chopped tomatoes. Add in the salt and mix well. This helps the tomatoes cook faster. Cover with a lid and cook until the tomatoes sweat and leave the water.

Add in jaggery powder and tamarind paste. Mix well. Cover and cook until the tomatoes are cooked and the water dries up a bit. Once it begins to dry, mash the tomatoes a bit.

Now add in the dry masalas. The powdered dry roast masala you prepared earlier, Kashmiri red chilli powder, and turmeric powder. Saute on medium to low heat until the oil starts appearing on the sides.

For tempering, heat 2 tsp oil in a tempering pan. Add in the mustard seeds and allow them to crackle. Add the hing and the curry leaves.

Pour the tempering on the tomato mixture. Mix well. Cook for a minute or two. The Tomato Thokku is ready to serve. Enjoy with idlis, dosas, or rice.