I had my first pisco sour a few nights ago at a tapas-style restaurant in Atlanta and boy am I crazy about this drink now. I tend to chose simple cocktails on the less sweet side, and this one fit the bill just right. The drink originated in Peru around 1900, and uses a Peruvian grape brandy, or pisco, to give it a pleasant bite. In fact, all you'll need is 4 ingredients to make this cocktail at home: pisco, sugar, fresh lime juice, and egg whites. Use pasteurized egg whites if raw eggs freak you out, but don't skip that step. The egg whites are the secret to giving this drink its creamy, frothy texture. Serve it straight up (without ice) and with a dash of bitters on top, if desired. Happy Thursday!