Method

1. Place the garlic in a mortar and pestle and pound until it becomes a smooth paste.
2. Add the pine nuts to the mortar and continue crushing them with the pestle until a sticky, slightly chunky, paste forms.
3. Gradually add the basil leaves, a handful at a time. Mash them with a sprinkle of salt to help break them down. Repeat this process until all the basil leaves are crushed.
4. Add the cheese to the mortar and slowly drizzle in olive oil while working it into the pesto with the pestle. Adjust the amount of olive oil to get your desired consistency.
5. The pesto can be served immediately with pasta or transferred to a jar or container. To keep it fresh, cover the surface of the pesto with a thin layer of olive oil, seal the container, and refrigerate.