01 - Fill a cocktail shaker with ice.
02 - Add gin, triple sec, lemon juice, and simple syrup if using to the shaker.
03 - Shake vigorously for 10 to 15 seconds until well chilled.
04 - Strain the mixture into a chilled highball or coupe glass filled with fresh ice.
05 - Top with soda water and gently stir to combine.
06 - Express oils from a strip of lemon peel over the drink by twisting it, then drop the peel into the glass as garnish.