Take the pan , heat the oil add mustard seed, cumin seed saute it well, then add small onion(chopped),red chilli,curry leaves , pinch of salt and hing. Mix it well till the onion are transparent, then add garlic saute well till it is half cooked in the medium heat. Now you can tomato, coriander powder, cumin powder, red chilli powder, turmeric powder ,tamarind juice. Cook these things well till the oil loose it out. Finally add the coconut milk, bring into one boil then finish it by adding coriander leaves.