Prep Glass: Fill an Old Fashioned glass with ice and give it a quick stir. Set it aside.
Add Egg White: Crack open 1 egg, separate white from yolk and pour the white into the shaker. Discard the yolk.
Add Absinthe: Pour 1 bar spoon Absinthe into the shaker.
Add Sugar: Add ¾ oz simple syrup.
Add Lemon & Lime Juice: Measure and pour ½ oz fresh lemon juice and ½ oz fresh lime juice into the shaker.
Add Whiskey: Finally, pour 2 oz Scotch Whiskey of your choice (preferably blended) into the shaker.
Dry Shake: Close the shaker well without adding ice and shake the ingredients vigorously for about 15 seconds.
Shake Well: Open the shaker and fill the shaker with ice. Close the shaker again and shake another time, for 15-20 seconds.
Strain: Discard the ice inside the Old Fashioned glass. Using the fine strainer and the cocktail strainer, strain the drink into the glass. Let it rest for 30 sec. - 1 minute.
Top Up with Soda Water: After waiting for more or less a minute, gently top up the drink with approx. 2 oz soda water (adjust to taste). The foam on top of the drink should slightly expand and rise.
Garnish: Garnish with a lemon zest twist. To do so, express the lemon peel on top of the drink and then place it on the rim of the glass or drop it directly inside. Serve immediately.