Toast the pine nuts: Begin by toasting the pine nuts in a dry skillet over medium-low heat. Stir frequently until they turn golden brown and emit a nutty aroma. Be cautious, as pine nuts can burn quickly. Once toasted, remove them from the heat and let them cool.
Prepare the basil: Wash and dry the fresh basil leaves thoroughly. Ensure they are completely dry to prevent the pesto from becoming watery. Remove any large stems as they can make the sauce bitter.
Blend the ingredients: In a food processor or blender, combine the toasted pine nuts, peeled garlic cloves, freshly grated Parmesan cheese, and the packed basil leaves. If you prefer a brighter pesto, you can also add a tablespoon of lemon juice at this stage. Pulse the mixture until it becomes a coarse paste.
Drizzle in the olive oil: Slowly drizzle in the extra virgin olive oil with the food processor or blender running. This gradual addition helps emulsify the sauce, creating a smooth and creamy consistency. Continue blending until the pesto reaches your desired texture, whether it's slightly chunky or perfectly smooth.
Season to taste: Add salt and freshly ground black pepper to the pesto and blend for a few more seconds. Taste the pesto and adjust the seasoning if necessary. Remember that Parmesan cheese is naturally salty, so go easy on the salt initially.
Store or serve: Homemade pesto is best enjoyed fresh, but you can store it in an airtight container in the refrigerator for up to a week. To prevent oxidation, press a layer of plastic wrap directly onto the surface of the pesto before sealing the container.