A Negroni is an Italian cocktail, made of one part gin, one part vermouth rosso, and one part Campari, garnished with orange peel. It is considered an aperitivo. Outside of Italy, an orange peel is often used in place of an orange slice. While the drink's origins are unknown, the most widely reported account is that it was first invented in Florence by the dauntless Italian Count Camillo Negroni in the early 20th century.
Add the gin, Campari and sweet vermouth to a mixing glass filled with ice, and stir until well-chilled.
Strain into a rocks glass filled with large ice cubes.
Garnish with an orange peel.