Add gin, fresh lemon juice, blue curaçao, elderflower liqueur, simple syrup, aquafaba (or egg white), and orange bitters to a cocktail shaker. Add the crushed ice. If using aquafaba or egg white, first perform a dry shake (no ice) for 15 seconds to emulsify, then add crushed ice and shake hard for 10–12 seconds until the outside of the shaker is frosty and chilled.

Double-strain

Open the shaker and double-strain the contents (use a Hawthorne strainer plus a fine mesh strainer) into a chilled coupe or Nick & Nora glass to remove ice shards and produce a silky texture and a pale blue hue from the blue curaçao balanced by the gin and elderflower.

Garnish & Presentation

If you want a theatrical 'wave' effect, carefully place a small piece of dry ice into a separate small glass container beside the coupe (do not put dry ice directly into the cocktail or let it contact skin). Pour a splash of warm water over the dry ice to create billowing fog while serving. Alternatively, float a lemon wheel on the surface of the cocktail and tuck an edible flower or mint sprig beside it.

Express a lemon twist over the drink (pinch the peel to release oils) and drop it in, or place the lemon wheel on the rim. Serve immediately while the foam is fresh and the cocktail is chilled.