Step 1.
- In a highball glass, muddle the mint leaves and elderflower syrup gently to release the mint oils.
Step 2.
- Add the lime juice and muddle slightly to combine with the mint.
Step 3.
- Fill the glass with crushed ice, then pour in the rum and top with soda water.
Step 4.
- Stir gently to combine the layers without disturbing the mint too much.
Step 5.
- Garnish with a sprig of mint and an elderflower blossom.