Place the sugar in a highball glass and add the lime juice. Gently muddle the mixture to dissolve the sugar.

Add the mint leaves and gently press with a muddler or spoon to release their flavor without tearing them.

Fill the glass with crushed ice and pour over rum, stirring until combined together.

Top up with club soda or sparkling water if desired, then stir again to combine all ingredients together.

Garnish your Cojito cocktail with extra mint leaves and serve!