In a tall glass, add 10-12 fresh mint leaves, 2 teaspoons of sugar, and juice of 1 lime (approximately 30 ml).
Using a muddler or the back of a spoon, gently crush the mint leaves to release their flavor. Be careful not to tear the leaves.
Fill the glass with crushed ice, leaving some space at the top.
Pour 60 ml of white rum over the crushed ice.
Top up the glass with soda water or sparkling water, and gently stir to combine the ingredients.
Garnish with a sprig of fresh mint and a slice of lime.