Add basil leaves, pine nuts, parmesan cheese, garlic, and lemon juice to food processor.
Pulse until pureéd and there are no large chunks.
Slowly pour olive oil into blender as you mix. If you are using a blender that doesn’t have an opening on top, periodically stop the blender, add in a little bit of oil, start it back up, and continue to blend until the oil is fully incorporated and smooth.