If using egg white, add gin, blue curaçao, fresh lemon juice, simple syrup and egg white to a cocktail shaker without ice. Dry-shake vigorously for 15–20 seconds to emulsify and build a creamy foam.

Shake with ice

Add plenty of ice to the shaker (about 1 cup). Shake hard for 10–15 seconds until the shaker is well-chilled and slightly frosted on the outside.

Strain

Double-strain the mixture into a chilled coupe or martini glass using a Hawthorne strainer and a fine-mesh strainer to remove ice shards and ensure a silky texture. If you prefer a lighter, slightly fizzy drink, pour into a highball glass over fresh ice and top with 1 oz club soda, stirring gently once.

Finish

If using a coupe/martini presentation, add 1 small dash of aromatic bitters onto the foam (optional) and use a toothpick to create a small design. If served tall, gently stir the soda once to combine.

Garnish

Express the oils of a lemon twist over the drink, then rub the rim with the twist and drop it into the glass. Alternatively, perch a lemon wheel on the rim and add a maraschino cherry if desired.