A Negroni is traditionally made with gin, but switching to whiskey can create an interesting variation. When you use Macallan whiskey (or any other single malt whiskey) instead of gin, it can more closely be considered a "Boulevardier", which is a whiskey-based variant of the Negroni.
1. 30 ml Macallan 12 year old double cask whisky
2. 30 ml of Campari
3. 30 ml sweet red vermouth (e.g. Carpano Antica Formula or Martini Rosso)
Course of action:
1. Add all the ingredients to a mixing glass with ice.
2. Stir well until the mixture is well cooled.
3. Strain the contents into a cool old fashioned glass filled with ice.
4. Decorate if necessary. with an orange peel.
Enjoy your Whiskey Negroni (Boulevardier) responsibly!