Flatiron favorite Cosme may be doted on by diners, but nobody puts Atla in a corner. The delightful little sibling on Lafayette Street stands proudly on its own two feet; and if the dazzling design—defined by black-and-white tiles, tiny wood tables, and a bustling, cosmopolitan scene—makes it feel like a contemporary Mexican terrace, well that’s the point.First things first: order a mezcal from the massive selection, then settle in to peruse the list of small plates. Arctic char tostada is a classic, but the scallop ceviche with cherry tomato is sure to garner a serious following. Other winners include meltingly tender birria, best with a side of warm tortillas.The handsome and none-too-sweet tres leches cake is a required finale.