Storm Chaser

Method

1. Pour the rum into a cocktail shaker with lots of ice cubes.
2. Add the orange bitters. Squeeze in the juice of ½ lime. Add the ginger syrup. Shake firmly, then strain into a martini glass – wet the rim with lime juice, then dip in caster sugar beforehand.
3. Top up with ginger ale, then add a sliver of lime zest.