Mix tomato puree, gram flour, turmeric powder, red chilli powder, salt and sugar. Whisk till well blended. Add two cups of water.
Heat a deep non-stick pan and roast mustard seeds, asafoetida, cumin seeds, curry leaves and whole red chilies.
Roast till a nice aroma is given out. Add the tomato mixture and bring it to a boil. Reduce heat and simmer for ten minutes. Serve hot garnished with chopped coriander leaves.