The rum provides smoothness and the bitters add a nice bite to this hybrid version of the old fashioned.
2 ounces aged rum
1/4 ounce simple syrup
1/4 teaspoon lime bitters
1/4 teaspoon Angostura bitters
1/2 teaspoon simple syrup
large mint leaf and/or lime peel twist
Place sugar and bitters in a mixing glass with a little water. Stir thoroughly and strain into an old fashioned glass over ice. Top with mint and lime.