How to Make It
Fill a highball glass with ice. Add the club soda, Tonic Syrup and bitters; stir well. Garnish with the lemon twist.
Tonic Syrup In a large saucepan, bring 16 ounces water to a boil. Stir in 1/2 cup sugar until dissolved. Whisk in 1 tablespoon honey, 1/2 coarsely chopped lemongrass stalk (tender inner core only), 1/4 teaspoon dried lavender buds and 1/2 tablespoon cinchona bark powder. Simmer over low heat until reduced by half, about 45 minutes. Strain through a fine sieve, then a fine coffee filter and finally through a paper coffee filter. Let cool, then add 1/2 ounce each of lemon juice and lime juice. Refrigerate the syrup for up to 2 weeks. Makes about 10 ounces.