Dry roast sesame, fenugreek and cumin seeds until sesame seeds pop. Grind it to a coarse powder.
Heat oil in a pan and fry onions and curry leaves until pink and add tomatoes to it.
Fry until tomatoes are mushy. Add coriander powder, chilli powder and sambar powder. Mix well.
Cool and grind this to a fine paste.
Heat oil in the same pan. crackle mustard seeds. Add small onions, garlic, curry leaves. Fry till slightly roasted.
Goes in the prepared masala paste and fry until moisture leaves.
Add tamarind water, turmeric powder, salt.
Mix well, close and cook on the medium heat until the oil leaves.
Open, add water to bring it to a thin consistency together with the roasted spice powder. Mix well and give it a boil.
Put off and serve hot with rice and stir fry.