3/4 ounce campari
2 ounces water
2 ounces bourbon
1 ounce sweet vermouth
orange bitters
orange twist, for garnish
Several hours before serving, mix together Campari and water and freeze in a square ice mold. When frozen, make the cocktail:
Place 2 Campari ice cubes in rocks glass. Pour all ingredients over ice cubes and garnish with a wide orange twist. Stir the drink to start the ice melting.
Source: saveur.com