To get the most out of fresh mint, place a few leaves in your hand and give it a smack to “wake up” the mint and release the oils without creating a bitter flavor.
In a tall glass (Tom Collins glass preferred) add mint, lemon juice, raspberries, and superfine sugar. Muddle ingredients gently making sure you do not tear the mint leaves.
Add crushed ice half way up the glass and add rum over ice. Using a long spoon gently mix ingredients together incorporating the rum into the muddled mixture.
Add crushed ice to top of glass and add sparkling mineral water. Stir ingredients together and top with fresh raspberries. Serve immediately.