Italian flat beans are also called Romano beans, and are wide, flattened versions of the more common green bean. The best Romano beans are bright green and crisp, with no soft spots or discoloration. Originally from Italy, this bean is grown and eaten in many other parts of the world. It can be steamed, stir-fried, braised, or served as a salad item, but should never be overcooked.
This kind of bean is also known as the Italian string bean, though most specimens have only a vestigial string. Flat beans grow to be about 5 to 6 inches in length (13 to 15 cm), and are about 0.5 inch (1 cm) across. Unlike conventional green beans, they are very thin, with occasional knobby protrusions on one side, where the immature seeds grow inside the pod. Some unusual varieties can have yellow or purplish pods.
The best Italian flat beans are fresh and crisp, with no mushiness, and don't bend easily without breaking. For this reason, the group of beans to which they belong is sometimes called the snap beans. Look for brightly-colored specimens, and avoid beans with brown or purple discoloration, dark areas, or fuzzy white mold. Older Romano beans may turn a slightly darker green and develop a wrinkled skin, with a softer, bendable texture that renders them appropriate only for soups and stews.
Italian cooks often braise these beans with tomatoes and meat, such as pancetta or bacon, or combine them with eggplant and capers in a caponata. They also work well when steamed until crisp-tender or microwaved. The best Italian flat beans will be brightly-colored when properly cooked, and provide some resistance to the bite. Pre-cooked, chilled beans can be topped with garlic, olive oil, or vinaigrette dressing as a salad, or parboiled, then sauteed and topped with oil or soy sauce, grated cheese, and other flavorful ingredients. Roasting flat beans with oil caramelizes the outside of their pods, producing a sweet, appealing taste.
These beans do poorly when cooked for long periods of time, losing their color and becoming mushy and relatively flavorless. Whenever possible, cook Italian flat beans only until they lose their raw flavor; the beans should not be fibrous or hard. Reserve longer cooking for older beans that won't provide a crisp, fresh flavor.