Add white rum, fresh lime juice, demerara syrup, and Angostura bitters to the shaker.
Shake vigorously for 10-12 seconds until well-chilled.
Double strain into a chilled coupe or Nick & Nora glass.
Garnish with a lime wheel if desired.
For demerara syrup:
Mix sugar and water in a small pot
Heat on medium, stirring until sugar dissolves
Let cool and store in fridge for up to 2 weeks
Notes
The drink works best with fresh lime juice - avoid bottled versions.Keep demerara syrup refrigerated in an airtight container.Regular simple syrup can replace demerara syrup, though the drink will lose some richness.White rums like Bacardi Superior or Havana Club 3 Year work well in this recipe