An authentic Genovese pesto. It's straight from Italy and you won't find a better recipe! This calls for a spoonful of Pecorino cheese, but you could also use all Parmesan in a pinch.
If you don't have a mortar and pestle, you can also use a food processor or blender. Chill the blade and container in the fridge for 1 hour and then process in pulses to avoid heating the pesto mixture. Add the basil, pine nuts and garlic in thirds, then follow with the cheese and oil as above.
To store in fridge for up to 1 month: place pesto in a jar, cover with olive oil and top with a lid.