Combine the tamarind water with the gram flour, chilli powder and coriander, in a saucepan. Break the cauliflower into sprigs and add to the ingre¬dients in the pan with the coconut milk. Fry the mustard seeds in a little oil until they begin to splutter. Add to the cauliflower. Season with salt. Cover with a lid and simmer gently until the cauli¬flower is tender. If necessary add a little water.