Periscope

Select and pre-chill a Cocktail Coupe.

Prepare a garnish by twisting a strip of grapefruit zest.

Shake all ingredients, including Hayman's London Dry Gin, elderflower liqueur, freshly squeezed lemon juice, freshly squeezed lime juice, and either pasteurized egg white or Fee Brothers Fee Foam, with ice. Then strain the mixture back into the shaker.

Dry shake the strained mixture without ice to enhance texture and aeration.

Fine strain the cocktail into the pre-chilled Coupe glass.

Express the grapefruit zest twist over the cocktail to release its aromatic oils, and then use it as a garnish.