Skinny Casper 1 Easy 5 Mins 1.5 oz citron vodka 1/2 oz St Germain 1 lime Splash simple syrup Sparkling water Add the citron vodka (1.5 oz), St Germain (1/2 oz), lime juice (1 lime) and simple syrup (splash) to a cocktail shaker and shake vigorously for about 15 seconds. Pour into a glass and top with sparkling water (or sprite if you don’t want it skinny).