Arugula pesto is a variation on the traditional pesto preparation that uses basil leaves. Pesto is a versatile sauce and condiment that is easily adapted to a wide span of different flavors, and substituting peppery arugula leaves for sweet basil is one way to adjust the taste. Like other versions of pesto, arugula pesto is made by crushing the leaves with olive oil, seasonings, and usually a hard cheese and some type of nut.
Classic Italian basil pesto is usually made using basil leaves, olive oil, Parmesan cheese, garlic, and pine nuts. These ingredients are ground together, either by use of the traditional mortar and pestle or with the more modern food processor until the mixture forms into a fragrant paste. Basil pesto can be transformed into arugula pesto simply by swapping out basil leaves for arugula leaves.
Arugula is a unique plant because it can be used either as a salad green or as an herb. The leaves have a zesty, peppery flavor; young, tender leaves are mild while more the mature, tougher leaves are much more pungent. Arugula can be mixed with salads to add a spicy tang or chopped fine and used as an herb like they are in arugula pesto. The pepper flavor and spiciness of an arugula pesto can be controlled or influence by how young or mature the arugula leaves are. Blanching the arugula leaves before making the pesto might help mellow the peppery flavor, and as an added bonus is thought to help keep the crushed leaves retain their vibrant green color instead of browning.
Since pesto can be crafted according to a huge variety of tastes and recipes, there are any number of ingredients that can be used in arugula pesto. Pine nuts can be traded for just about any other type of nut, such as walnuts, pecans, or hazelnuts. Similarly, the Parmesan cheese is merely a suggestion – any hard cheese will contribute the salty component while also lending its own unique flavor. Olive oil is generally the best choice for the oil component because it complements the peppery arugula without competing with it — if a different oil suits the cook’s fancy, however, substitutions are certainly possible.
Once the arugula pesto is complete it can be used in many different dishes. The pesto can be served as a sauce over pasta or potatoes, or a dollop can accompany proteins ranging from steaks to seafood. A pesto without nuts can be added as a seasoning agent to soups or stews to lend a bold, herbaceous flavor. Even more simply, a thicker pesto can be eaten by itself over bread and crackers, or mixed with soft cheeses to make a flavored spread.