The boulevardier cocktail is an alcoholic drink composed of whiskey, sweet vermouth, and Campari. Loosely translated, a boulevardier is a man-about-town. Its creator, Erskine Gwynne, was an American-born writer who founded a monthly magazine in Paris called Boulevardier, which appeared in the 1920s. The boulevardier is similar to a Negroni, sharing two of its three ingredients with the main spirit being swapped from gin to either bourbon or rye whiskey.
Add all ingredients into a cocktail shaker with ice and shake for 20-30 seconds or until chilled. Strain into a rocks glass over single ice cube. Garnish with an orange peel.