Add the mint sprigs and sugar to a highball glass. Gently muddle to release the mint oils without tearing the leaves.
Add the fresh lime juice and stir briefly to dissolve the sugar.
Fill the glass with crushed or cubed ice.
Pour in the white rum and stir gently to combine all ingredients.
Top with soda water and give one final light stir.
Garnish with a fresh sprig of mint and a slice of lime.
Muddle mint gently - pressing too hard crushes the stems and releases bitter chlorophyll. You want bruised leaves, not pulp.
My Bar Shelf reads your shelf and shows you every cocktail you can make from what you already own, including Mojito.