Passion Fruit Sour

Steps

1. Measure bourbon, Proof Syrup, and lime juice into cocktail shaker.
2. If using egg white, add egg white and one whole ice cube. If skipping the egg white, fill shaker about halfway with ice.
3. Shake. If using egg white, shake until ice cube is dissolved, by which point the egg white should be nicely frothy. Otherwise, shake until well chilled and combined.
4. Strain into a chilled coupe glass.
5. Garnish with lime wheel and a shake of bitters.