What is the garnish used for a Dry Manhattan?

The garnish used for a Dry Manhattan is an olive. In cocktail preparation, the type of garnish can greatly influence the drink's flavor profile and presentation. For a Dry Manhattan, which is typically made with dry vermouth and whiskey, the olive complements the drink's character by adding a subtle briny note that balances the sweetness of the whiskey while not overpowering the drink’s dry nature.

Other garnishes like a cherry or lemon twist may be associated with other variations of the Manhattan cocktail, such as a Sweet Manhattan or a different style altogether. Hazelnuts are not a traditional garnish for any version of the Manhattan, making them an unlikely choice. Thus, the olive is specifically recognized as the appropriate garnish for a Dry Manhattan.