"Sweet anise" can be a confusing term, because it is used to describe two different types of plants used in cooking — plants with a similar taste but a different appearance. The term is most commonly used to describe the bulb and fronds of the fennel plant, although it also is sometimes used to describe dishes that are sweet and contain the seeds of the anise plant, as is the case with dishes such as sweet anise bread. It is easy to tell fennel from anise because the anise plant is cultivated exclusively for the seeds it produces, while the fennel plant is generally sold as fronds and stalks attached to a large white bulb at the base. The flavors of the two versions of sweet anise are similar, both having a strong licorice taste, although fennel is considered to be sweeter and lighter. Neither fennel nor anise should be confused with star anise, which is a seed pod that grows on an evergreen tree and is unrelated except, again, in taste.
The reason there is a similarity in taste between the different plants is because of a chemical known as anethole, which produces the licorice flavor. In nature, the plants are easily distinguished. The flowers of the fennel and anise plants are similar in structure, but the fennel plant has distinctive, misty-looking green fronds whereas the anise plant does not. The tree from which star anise comes is completely different, growing primarily in Asia.
The version of sweet anise that is really fennel has a number of culinary uses. The fronds can be diced and used in salads or as a spice like any other fresh herb. The bulb can be sliced into pieces and added to any dish, where it will provide a fresh, crisp flavor. When cooked, the bulb can be formed into a very stiff paste that can be mixed with mashed potatoes to lighten the flavor of a traditionally heavy dish. Slices of the bulb also can be quickly fried in hot oil to create fennel chips as a snack food, or used as a garnish in a larger meal.
The uses for the type of sweet anise that refers to the actual seeds of an anise plant are more distinct. They are a common spice, usually dried, that can be added to sausages or pickling spices. In some areas, anise seeds are used in the production of liquors such as ouzo in Greece, which has a syrupy texture and sweet anise flavor.