In a pan, heat 1 tbsp oil. Add chopped tomatoes and cook them until mushy on low flame. Cool them down completely.
In a mixer jar, add cooked and cooled down tomatoes along with tamarind pulp, red chilli powder, mustard powder, turmeric powder and salt. Pulse it a 2-3 times until the mixture is blended coarse. Remove it onto a bowl. Mix in the garlic pods.
In a pan, heat gingelly oil. Add mustard seeds and dried red chillies (cut in half). As the mustard seeds splutter, add asafoetida and switch off the flame.
Once the tempering cools down, add it to the ground mixture. Mix it well. Let it sit for a day or two before serving.
Store it in a clean dry glass jar in the refrigerator for upto 3 weeks.