Makes 1 strong cocktail.
3 ounces pisco (grape brandy)
1 ounce lime juice
1/2 to 1 ounce simple syrup, to taste
1 egg white
a handful of ice cubes
Angostura bitters (optional but advised)
Put a cocktail glass in the freezer to chill. In a blender, combine the pisco, juice, simple syrup, egg white, and ice. Blend until the ice is completely crushed and mostly melts away. (Lack a blender? Use a cocktail shaker and brute upper body strength).
Pour into the chilled glass. A layer of foam will rise to the top. Add a dash or two of bitters to the foam for garnish. Drink and rejoice.