Instructions
- Cut the watermelon into small cubes and puree it until smooth, then strain to remove pulp, yielding about 1 cup of juice.
- In a highball glass, muddle the mint leaves and lime juice gently to release the mint oils.
- Fill the glass with ice, then add the watermelon juice and rum.
- Top up with soda water and stir gently to combine.
- Garnish with a sprig of mint and a wedge of watermelon.