Muddle the sugar. Add the sugar cube to a lowball glass. Top with the water and bitters, then use a muddler (or the end of a wooden spoon) to combine until the sugar is nearly dissolved.
Mix. Add the bourbon and a large ice cube. Stir vigorously for 10 seconds or until the liquid is chilled.
Garnish. Add a cocktail cherry or two, if desired. Gently twist the orange peel directly over the glass, in order to express its oil into the cocktail, then add the orange peel as a garnish.
Serve. Serve immediately and enjoy. Cheers!
Notes
Sweetener options: Feel free to use a different type of granulated sugar if you prefer, such as coconut sugar. Or you can sub in a liquid sweetener, such as maple syrup or simple syrup, in which case you can just directly mix the sweetener and bitters in with the bourbon.Orange peel: I also love to run the orange peel around the rim of the glass before mixing the drink to add an extra hint of orange flavor.