Instructions

1. Add the basil leaves, St. Germain elderflower liqueur, lemon juice and gin to a cocktail shaker. Half fill with ice and muddle vigorously to bruise the basil.
2. Shake, then strain into a cocktail glass. Don't worry if a few flecks of basil make it through.
3. Top with a quick splash of club soda and serve immediately with garnish of basil sprig.