In a chilled cooler or long drink glass, muddle the syrup, mint leaves, juice and pulp from the 1/2 lime, and lemon zest.
Note: for best results, break and partially tear the mint leaves first to release their flavour and facilitate the muddling process.
Add rum, triple sec, lime juice, and bitters.
Fill glass approximately 2/3-3/4 full of cracked ice and stir briskly until the glass frosts.
Almost fill glass with ginger ale and stir gently to mix ingredients throughout (including mint).
Float a bar spoon of dark rum on top.
Garnish with a slice of lime and a mint sprig (allowing the mint to protrude from the top).
Stick your nose right into the mint while drinking and take a deep breath to enjoy the mixed aromas of the lime, mint, and rum… it doesn't get any better!