Place basil, garlic, pine nuts, cheese and salt into the bowl of a food processor and pulse until finely chopped. Scrape down bowl sides with a spatula.
With the food processor running, add olive oil in a steady stream and process until smooth. (The less time this takes the better as heat from the blade can affect the flavor.) Taste and add more salt if needed.
TIP: Put your food processor blade in the freezer 15 minutes before you plan to make the pesto.