Limoncello is a vibrantly colored digestif that goes down easy on a hot summer’s day. Although the sweet liqueur is most often served, chilled, in a shot glass, it is meant to be sipped slowly after your meal. And although easy to make, limoncello has a complicated — and contested — history. Some people believe that Italian monks first made the spirit as early as the Middle Ages; others credit Southern Italian fishermen who were thought to drink it upon returning to shore to warm themselves and fight off colds. But most accounts attribute its creation to Maria Antonia Farace, who reportedly lived on a small island off Italy’s southern…