Add whiskey, Campari, vermouth and lime juice to an ice-filled 4-cup glass measuring cup. Stir for 20 to 30 seconds or until chilled.
2
Place 1 (2-in.-sq.) ice cube in each of 2 (10-oz.) rocks glasses. Strain drink mixture with a slotted spoon or through a small fine-mesh sieve into prepared glasses. Garnish with lime peel.