Cupcakes are old news. The newest sugary sensation to sweep New York City is the Cronut -- the croissant-doughnut hybrid created by Dominque Ansel at his SoHo bakery last month, in which flaky laminated dough is cut into a doughnut shape, deep-fried, rolled in sugar, then glazed. With production of the pastry limited to 300 a day, Cronut mania has created long lines and even given rise to a seedy underworld of Cronut scalping. As executive food director Lucinda Scala Quinn says, "It...