(2 to 3)
Fill with ice and soda water
Place sugar, a large pinch (small handful) of mint, and splash of soda water in a pint glass. Use muddler to lightly press mint and dissolve sugar until it smells of spearmint gum. Squeeze both halves of lime into the glass, leaving one hull in the mixture. Add rum, stir, and fill with ice. Top with soda water, garnish with mint sprig and serve.