- In an airtight container, combine the lemonade, rum, lime juice, mint and lime zest. Freeze for 8 hours or overnight.
- Break the frozen juice mixture with a fork until it has the texture of a slushie.
- In a long, chilled glass, fill with half slush and half sparkling water or club soda. Blend with a spoon and serve with a straw.
- The remaining of the preparation can be stored in the freezer for several weeks.