I've only had the dish in Kerala, but apparently, it's popular in Tamil Nadu and Sri Lanka -- or so holds The Village Voice, which tipped me off to a must-visit venue: Bownies, 143-05 45th Ave., in Flushing, Queens; they note, "Sri Lankan food in Queens at this luncheonette, serving the broding, spice-laced 'black curries' (pick lamb); mellow, coconut-laced fish curries (pick kingfish); and breads like appams (weekends only) and outsize rotis that make Ceylonese cooking delightfully unique."
... I think I know where I'm headed this weekend. Smell ya later, Colombian bakeries of Sunnyside! I need a little spice in my life!