What is the primary component of a traditional Italian pesto sauce?

The primary component of a traditional Italian pesto sauce is fresh basil. Pesto originates from the Liguria region of Italy, and the term "pesto" comes from the Italian word "pestare," which means to crush or pound. Fresh basil leaves are the base of this sauce, providing a vibrant green color and a distinctive aromatic flavor.

In making traditional pesto, the fresh basil is typically combined with garlic, pine nuts, Parmesan cheese, and olive oil, but the basil is what defines its character and richness. This herb plays a crucial role in creating the fresh and bright flavors that pesto is known for, making it the star ingredient in the sauce.