Which cocktail is traditionally garnished with a twist of lemon?

A gin martini is traditionally garnished with a twist of lemon. This garnish enhances the drink's botanical flavors and adds a subtle citrus aroma, which complements the gin's characteristics perfectly. The twist is created by expressing the oils from the lemon peel over the surface of the cocktail, enriching the drinking experience with a fragrant note that emphasizes the crispness and complexity of the gin.

In contrast, other cocktails listed do not use a lemon twist as a standard garnish. For instance, a mojito is typically garnished with fresh mint leaves, while a margarita usually features a lime wedge or salt rim. The old fashioned is often garnished with either an orange slice or a cherry, emphasizing different flavor profiles than those found in a gin martini. The unique pairing of the lemon twist with the gin martini is what sets it apart as the traditional choice for that cocktail.