Soak tamarind in hot water.
Heat a pan with oil, add chopped onions, green chillies, garlic cloves and sauté them until they change the colour. Transfer them to a plate.
In the same pan add chopped tomatoes along with little salt, so that tomatoes can cook fast.
Next, add chopped coriander leaves and sauté it until it is cooked. Transfer to a plate to cool down.
Add all the cooled ingredients into a mixer along with tamarind, salt and grind into a coarse paste.
Heat 2 teaspoon of oil, add urad dal, mustard seeds and dry red chillies. When the mustard seeds crackle, add the ground paste and mix well for 2-3 min and switch off the flame and transfer to a bowl.