Chill the Prosecco, St. Germain, and club soda ahead of time so the ice doesn’t melt too quickly and dilute the drink.I like to use a cocktail stirrer when making these drinks since it does a good job of combining the liquids without popping bubbles. If you don’t have one, just stir gently.Have any elderflower plants around you? This drink is beautiful with some handpicked elderflower blossoms as garnish.