Fill a cocktail shaker with ice. Pour the butterfly pea flower gin, B&B liqueur, and hyssop syrup over the ice. Stir the cocktail with the ice for at least 10 to 15 seconds. Strain the cocktail into the prepared coupe glass. Garnish with a lemon twist if desired. Just before serving, drizzle the lemon juice into the cocktail and watch it transform right before your eyes!