In the bowl of a food processor, combine the basil leaves, garlic, pine nuts, and a pinch of kosher salt. Pulse until finely chopped.
Add the grated Parmesan cheese and pulse a few more times to combine.
While the food processor is running, slowly pour in the extra virgin olive oil until the mixture is smooth and creamy. Add a squeeze of lemon juice if desired.
Taste your pesto and adjust the seasoning if necessary.
