In a Kir Royal, which beverage is used as the base?

A Kir Royal is traditionally made with champagne as the base beverage. The classic version of this cocktail is a mixture of crème de cassis, a blackcurrant liqueur, and topped with champagne. This not only enhances the flavor profile but also gives it a celebratory and elegant characteristic associated with champagne.

While other sparkling wines such as prosecco could be used in variations of the drink, the authentic Kir Royal specifically calls for champagne, making it the definitive choice in this context. Red wine and white wine do not align with the traditional preparation of a Kir Royal, as they would alter the intended taste and experience of this cocktail.