Combine gin, elderflower liqueur, fresh lemon juice, simple syrup, egg white (or aquafaba), and vanilla bitters in a cocktail shaker without ice. Seal and shake vigorously for 20–30 seconds to emulsify and create a silky foam.

Wet shake

Add ice to the shaker (enough to fill it halfway). Shake again hard for 12–15 seconds until the shaker is very cold to the touch and the foam is glossy and thick.

Fine strain

Double strain the cocktail into a chilled coupe or Nick & Nora glass using a Hawthorne strainer and a fine mesh sieve to ensure a smooth, silky texture free of ice shards or coagulated egg bits.

Adjust silkiness (optional)

If the foam is too stiff or the texture too dense, gently stir in up to 0.25 oz chilled water in the glass to soften the body, then allow the foam to settle for 10–20 seconds.

Garnish & Finish

Express the lemon zest over the surface of the foam to release the oils, then drop the twist on the rim or float it briefly on the foam.

Gently place the edible viola or rose petal in the center of the foam. If using, lay the dried lavender sprig lightly across the petal for a delicate floral aroma.

Serve immediately, presenting the drink as 'silky smooth with delicate floral notes and a clean, elegant finish.'