1 1/2 oz lime juice
1 tsp superfine sugar
2 oz gin
1 dash bitters
3 oz club soda

In a shaker half-filled with ice cubes, combine the lime juice, sugar, gin, and bitters. Shake well. Almost fill a collins glass with ice cubes. Stir until the glass is frosted. Strain the mixture in the shaker into the glass and add the club soda.