What garnish is commonly used in a Rob Roy?

In a Rob Roy, the classic garnish is a cherry. This cocktail, which is a variation of the Manhattan, typically consists of Scotch whisky, sweet vermouth, and bitters. The cherry garnish complements the rich flavors of the whisky and sweet vermouth, adding a touch of sweetness and a visual contrast to the drink.

Although other options like lemon twist or orange slice are common garnishes for different cocktails, they do not align with the traditional presentation of a Rob Roy. The olive, often used in Martinis, would also not provide the flavor profile that complements this specific drink. Thus, a cherry serves not only as a decorative element but also enhances the overall drinking experience.