Muddle sugar cube (white) and bitter in a chilled rocks glass. Fill with ice cubes. Add bourbon. Stir. Garnish with orange.
The perfect way to make an Old-Fashioned has been disputed, but one thing is clear. Never was it more needed than during prohibition; it's the best way ever invented to improve the taste of bad liquor. Now made with the purest of ingredients, it's a helluva classy drink. Traditionally bourbon-based.