The primary ingredient in traditional pesto is basil. This fragrant herb provides the characteristic flavor of pesto, a classic Italian sauce that originates from Genoa. In traditional recipes, fresh basil leaves are combined with pine nuts, garlic, Parmigiano-Reggiano cheese, and olive oil to create a vibrant green paste. The ingredients are typically crushed together using a mortar and pestle, although blenders and food processors are commonly used today for convenience. Pesto is versatile, often used as a pasta sauce, spread, or marinade. Its fresh, aromatic taste makes it a beloved component in Mediterranean cuisine.