The primary ingredient in traditional pesto sauce is basil. This aromatic herb lends the sauce its distinctive green color and flavor. Traditional pesto, originating from the Italian region of Liguria, is made by blending fresh basil leaves with garlic, pine nuts, Parmesan cheese, and olive oil. The ingredients are typically crushed together using a mortar and pestle, although modern recipes sometimes use blenders or food processors. Pesto is widely used as a pasta sauce, but it can also be a delicious spread for sandwiches or a flavorful seasoning for various dishes. Its fresh taste captures the essence of Italian cuisine.