In a pitcher, combine the lemonade and vodka. Slowly stir in the champagne. Pour into ice-filled glasses and garnish with mint sprigs.
Cook's Note: To make vanilla-flavored vodka, place 3 whole vanilla beans in a 750 ml bottle of plain vodka. Place the bottle in a cool dark place for at least 10 days to allow the vanilla to infuse the vodka. Open the bottle occasionally during the infusion time.