1. Add the lime and sugar to your Collins glass and muddle with a muddler.
  2. Add the mint leaves and place the flat end of a bar spoon in the glass.
  3. Fill the glass with crushed ice and pour in the rum.
  4. Rapidly raise and lower the spoon the thoroughly mix the drink.
  5. Top with soda.
  6. Garnish with a sprig of mint, rubbing the leaves before serving to release the bouquet.