What is the primary ingredient found in traditional pesto sauce?

The primary ingredient found in traditional pesto sauce is basil. This fragrant herb is the defining component of the sauce, providing its characteristic flavor and aroma. The traditional recipe for pesto, known as "pesto alla Genovese," originated in Genoa, Italy, and uses fresh basil leaves as the foundation. The leaves are typically combined with garlic, pine nuts, Parmesan cheese, and olive oil to create a vibrant green sauce that can be used in various dishes.

While garlic, olive oil, and Parmesan cheese are significant components of the sauce, they serve to enhance and complement the fresh basil rather than being the main ingredient. The balance of these ingredients contributes to the unique taste of pesto, but it is the basil that truly defines its identity.