The traditional amaretto sour you’d get in any bar is a sickly-sweet mixture of amaretto and sour mix. We much prefer expert bartender Jeffrey Morgenthaler’s version, with bourbon adding a little depth. He specifically calls for cask-aged bourbon, which stands up well to the otherwise-cloying sweetness of amaretto.
Like all egg white (or aquafaba) drinks, you should dry-shake first without ice, and then again with ice, and you should double-strain it through both your shaker’s strainer and a fine mesh strainer.
