Add gin, dry vermouth, fresh lime juice, green chartreuse, simple syrup, and egg white (or aquafaba) into a cocktail shaker without ice. Seal and shake vigorously for 15–20 seconds to emulsify and create a frothy texture.

Wet shake

Add a generous handful of ice to the shaker (about 1 cup). Shake again vigorously for 10–15 seconds until the shaker is well chilled and the exterior becomes frosty.

Strain

Double-strain the mixture through a fine mesh strainer into a chilled coupe or Nick & Nora glass to remove ice shards and achieve a silky texture.

Optional top

If you want a little effervescence, gently top with about 1 oz club soda poured down the side of the glass so the foam remains intact.

Garnish & Finish

Express oils from a lime twist over the surface of the cocktail, then drop the twist into the glass or rest a lime wheel on the rim.

Gently slap the mint sprig between your palms to release aroma and place it on the foam as a fragrant accent (optional). If using edible silver dust, very lightly sprinkle 1/4 tsp on the foam for a theatrical finish.

Serve immediately while the foam is fresh and the cocktail is chilled.