Hazelnut syrup is a sweet, nutty-flavored syrup made from the essence of hazelnuts, sugar, and water. It is a popular ingredient in both non-alcoholic and alcoholic beverages, adding a rich, toasty flavor that complements a variety of drinks. This syrup can be found in many coffee shops, used to enhance lattes, cappuccinos, and other coffee-based drinks with its distinctive nutty profile.

In the context of cocktails, hazelnut syrup is often used to introduce a unique, aromatic sweetness that pairs well with a range of spirits. It can be particularly effective in enhancing the flavors of whiskey, rum, and brandy-based drinks, adding depth and complexity. When creating cocktails, bartenders might use hazelnut syrup to craft signature drinks or to add a twist to classic cocktails, such as an Old Fashioned or a Brandy Alexander. Its versatility makes it a valuable addition to any mixologist's toolkit, providing a deliciously nutty undertone that can elevate a drink's overall character.