The Pisco Sour is perhaps the most famous drink that uses this special South American form of brandy. The key ratios as standardized in Peru is 3 parts Pisco, 1 part lime juice, and 1 part simple syrup. The egg white adds a luscious mouth-feel to it, and the bitters dashed on top add both a nice aromatic nose to it, plus perhaps more importantly will eliminate the "wet dog" smell that an egg white foam will cause.