Prep Glass: Fill a coupe glass with ice and set it aside.
Add Egg White: Crack open an egg, separate white from yolk and pour 1 egg white into the shaker. Discard the yolk.
Add Simple Syrup: Add ½ oz simple syrup.
Add Lemon Juice: Measure and pour 1 oz fresh lemon juice into the shaker.
Add Bourbon: Pour 2 oz Bourbon into the shaker.
Shake Well: Fill the shaker with ice. Close it well and shake the ingredients vigorously for about 15 seconds.
Dry Shake: Open the shaker. Using the cocktail strainer, pour the liquid in the other tin and discard the ice. Close the shaker again and shake another time, for 15-20 seconds, without ice this time.
Strain: Discard the ice inside the coupe glass. Using the fine strainer, strain the mixture into the chilled glass.
Garnish: Express the lemon zest on top of the glass (you can either discard it after or place it on the rim of the glass for an added citrus touch). Serve immediately.