Combine the basil leaves and pine nuts in a food processor. Use the pulse setting until chopped into fine pieces. Use a spatula to scrape down the sides so the mixture is at the bottom of the food processor bowl.
Add the cheese and garlic and pulse to combine. Scrape down the sides as needed.
Pour in the olive oil a little bit at a time. Keep the food processor running while adding the olive oil.
Season with salt and pepper to taste.