It's visually impressive and makes an exceedingly tasty vegetarian main course. This is essentially a spiced version of the British classic cauliflower cheese in a mild curry sauce, which is ripe for improvisation. If you're wishing for a bolder rendition, increase the quantity of cayenne, add a few cumin seeds and perhaps stir in some chopped green chile. For the best presentation, roast whole heads, but you may cut them into halves or quarters…