1 ounce mint leaves, torn in half
2 ounces fresh lime juice
1 ½ ounces white rum
1 teaspoon extra-fine granulated sugar
Crushed ice
4 ounces club soda

Muddle (crush with a pestle) the mint with the lime juice in the bottom of a tall cocktail glass.
Add the rum, sugar, crushed ice and soda in a cocktail shaker, and shake.
Strain with ice, mint, and a lime wedge.