
Irish whiskey is distilled and matured at least three years on the island of Ireland. Most of it is light and soft: clean, fruity and all but smokeless.
The closest match. An unpeated one works in the same amount.
Works too, but gives a heavier, sweeter drink with more vanilla.
Triple distillation — one pass more than in Scotland — is where the softness comes from, though it was never a rule.
Cosmopolitan Cocktail (1927 recipe)
Blended Scotch whisky, Irish whiskey, Vodka, Swedish Punsch liqueur