There is nothing special about this particular recipe, but given the magnificence of a real pisco sour one doesn't want to mess around with unecessary embellishments. If you have an aversion to raw egg whites this is sadly not for you, but for everyone else here you have it all: fizz, froth, sour, sweet, bitter and beautiful.
I am posting two recipes, the classic, shaken in a shaker but iceless in the glass, and the version you are more likley to find in bars. The first is best but for those who love crushed ice the second is user-friendlier.
I append the brilliant pisco sour-making scene from Heddy Hongimann's great documentary Oblivion, in which the bartender, while concocting his magic, refers to Peruvian politics as a badly made cocktail. Enjoy!