Before your cocktail party, prepare your glasses with powdered hibiscus and powdered sugar, and pre-mix the St. Germain, lemon and spiced hibiscus syrup. That way, when it’s time to serve, simply add 1 oz. of your mixer to 3 oz. of prosecco in a cocktail shaker (for 1 cocktail), gently stir with ice, pour and serve. You can even pour the champagne in the glasses, then add the hibiscus mixer for a different look.