Wash hands with soap and water.

Pat basil dry with a paper towel after washing. Place the basil and nuts in a food processor or blender. Pulse until combined. Scrape down sides with a spatula or spoon.

Add garlic and cheese to basil mixture and pulse until combined. Scrape down sides again with a spatula or spoon.

While the food processor is running, slowly add half of the olive oil. Stop the food processor and scrape down sides again. Start the food processor and add remaining oil.

Add salt and pepper, if desired.

Store leftovers in a sealed container in the refrigerator, or freeze for up to three months.