We recommend Carpano Antica Sweet Vermouth(or another rich sweet vermouth such as Cocchi Torino) for this cocktail.
Stir Ingredients in a mixing glass, and strain over fresh ice, or stir to the appropriate temperature and dilution and strain into a chilled, stemmed glass.
You may want to add a little less of the sweet vermouth and Campari according to personal taste. Garnish with an orange peel expressed and set along the top of the cocktail.