Add all ingredients to a cocktail shaker without ice. (This is called a “dry shake”.) Shake for 20-30 seconds.*
Then, add ice and shake for another 30-45 seconds.
Strain into a coupe glass. Garnish with a lemon twist.
Notes
*You may want to shake over a sink because the lack of ice will mean that the metal cocktail shaker won't contract to create a tight seal. I.e. it's gonna leak.
Keyword egg white, gin, lemon, lemon juice, orange liqueur, simple syrup, white lady