The Negroni is a classic cocktail that was created by, and named for, Count Camillo Negroni in 1919 at Caffè Casoni in Florence, Italy. It was made as a variation of another Italian cocktail called the Americano that uses equal-parts gin, sweet vermouth, Campari, and citrus but omits the soda water.
Add gin, vermouth, and Campari to a mixing glass.
Fill mixing glass with cubed ice.
Using a bar spoon, stir for 30-45 seconds until well-chilled and slightly diluted.
Add a clear ice cube to a lowball glass.
Using a julep strainer, strain into lowball glass.
Express orange slice into glass.
Garnish with orange peel.