In a mixing glass, add the cinnamon bark syrup, rum, bourbon and bitters. Fill with ice cubes and mix by holding the spoon like a pen and stirring clockwise. To serve, place a large ice cube into a glass and strain. Run the orange twist around the rim, add to the cocktail and serve.
Cinnamon Bark Syrup
In a saucepan, combine equal parts sugar and water. Break up the cinnamon bark (sticks), add to the simple syrup mixture, and bring to a boil. Remove from heat, cool, and strain.