The main ingredient found in pesto sauce is basil, a fragrant herb that gives pesto its distinctive flavor. Traditional pesto originates from the Liguria region of Italy and is made by blending fresh basil leaves with pine nuts, garlic, Parmesan cheese, and olive oil. This combination creates a rich, green sauce that can be used in various dishes, such as pasta, sandwiches, and salads. The process typically involves grinding the ingredients together using a mortar and pestle or a food processor to achieve a chunky yet creamy consistency. Pesto is appreciated for its freshness and versatility in enhancing numerous culinary creations.