Instructions
- In a cocktail shaker, muddle fresh mint leaves with sugar and grapefruit juice until the mint is fragrant and the sugar dissolves.
- Add the rum and ice to the shaker, then shake well until chilled.
- Strain the mixture into a highball glass filled with fresh ice.
- Top with club soda to add a refreshing fizz.
- Garnish with a sprig of mint and a slice of grapefruit.