What nut is used in traditional pesto alla genovese?

Traditional pesto alla genovese is made with pine nuts.

Pesto alla genovese comes from Liguria, the northwestern Italian region whose capital is Genoa. The name refers to the preparation method: ingredients are traditionally crushed or pounded together rather than cooked. Fresh Genovese basil is combined with pine nuts, garlic, salt, hard cheeses such as Parmigiano-Reggiano and Fiore Sardo, and extra-virgin olive oil.

Pine nuts provide a mild, buttery richness and help give the sauce its smooth body. They are not merely a generic garnish; they are part of the traditional Genoese formula. The basil, garlic, cheese, and oil are equally important to the sauce’s characteristic flavor.

Cashews, almonds, and walnuts appear in modern or regional substitutes, often because they are cheaper or easier to find. Walnuts have also been used historically in some inland versions, but that does not make them the canonical nut for pesto alla genovese. Similar green sauces may be called pesto, yet traditional Genoese pesto specifically points to pine nuts.