Wash and dry your basil leaves thoroughly to remove any dirt or debris. Toast your pine nuts lightly in a pan to bring out their nutty flavor, and peel your garlic cloves.

In a food processor, add the basil leaves, garlic, pine nuts, and Parmesan cheese. Pulse a few times until the mixture becomes a rough paste. Then, with the motor running, slowly drizzle in the olive oil until the mixture becomes smooth and creamy.

If the pesto is too thick, you can add a little more olive oil or even a splash of water. Taste and adjust seasoning by adding salt, more garlic, or even a squeeze of lemon juice for brightness.

Transfer your pesto to an airtight container and drizzle a thin layer of olive oil on top to prevent oxidation. Store it in the fridge for up to a week, or freeze it for longer storage.