Add the egg white, lemon juice, simple syrup, and bourbon to a cocktail shaker.

Dry shake (shaking without ice) for about 20 seconds. This is what starts aerating the egg white and gives you that beautiful foam.

Add ice (my trick is a handful of regular ice plus 1 large cube) and shake again until the shaker is nice and cold.

Double strain into a chilled coupe glass. Let the foam settle for a few seconds, then garnish with three drops of aromatic bitters.