To a tall glass add the lime juice and sugar and stir until sugar dissolves (if using chopped limes bash with pestle until sugar dissolves - this way can take time but so worth it).

Add the mint leaves to glass then fill with crushed ice until an inch from top of glass. Using a pestle or long spoon try and crush the mint leaves through the ice.

Pour in the rum and stir.

Finish off with extra mint leaves for decoration and more ice if needed.