3-4 oz White Rum
Havana Club is strongly recommended.
Juice of 1 Lime
1-2 tsp Sugar
Brown's better than white
Some Mint Springs
Insider tend to use Schweppes Ginger Ale instead
Dissolve the sugar in the lime juice in a tall glass. Gently crush the mint in the glass. Add the white rum, crushed ice, then fill with soda water, stir and serve, garnished with a mint sprig. If you're using Schweppes Ginger Ale, just reduce the amount of sugar.