This venue is closed. Paisley damask chairs and photos of the Taj Mahal certainly convey “Indian restaurant’ to tourists and theatergoers who randomly fall into Purnima. But when Vikas Khanna’s food arrives they thank their lucky stars they did. Beyond his culinary training, he is an instinctive chef whose dishes just get it right. A native of Amritsar in northern India who previously helmed Salaam Bombay downtown, Khanna emerged triumphant in a notorious episode of Gordon Ramsey’s Fox reality show, “Kitchen Nightmares.” (Khanna’s task was to turn a mouse-infested saloon into a refined Indian eatery.) He opened Purnima on those premises in 2007 with Ramsey’s blessing and a name meaning “full moon” in Sanskrit. His menu, partly produced in a round tandoor oven, offers modern pan-Subcontinental fare that is distinctly yet delicately spiced. Lamb morongo presents lusciously braised chunks in an outrageously tasty mango-sweetened puree, and earthy Kashmiri aloo dum is simply potatoes with cashews and dates. For New Yorkers used to cheap, oily, one-note curries served in tin crocks, Purnima demonstrates just how elegant and contemporary India’s varied cuisine can be.