2 oz Pisco
1 oz Lime juice (or lemon)
1⁄2 oz Simple syrup
1⁄2 oz Egg white
Shake without ice, then add ice and shake again until frothy. Strain into chilled flute. Garnish with drops of bitters.
Both Chile and Peru claim this as their drink. The South American "Limon" is closer to the North American lime.
Gary Regan, The Joy of Mixology. http://en.wikipedia.org/wiki/Pisco_sour
Pisco, Bitters, Lime juice, Simple syrup, Egg white