Step 1: Toast the pine nuts in a small dry skillet over medium heat for 2-3 minutes until golden brown and fragrant. Remove immediately to prevent burning.
Step 2: Place the fresh basil leaves and toasted pine nuts into a food processor and pulse several times until coarsely chopped.
Step 3: Add the minced garlic and grated parmesan cheese to the mixture. Pulse a few more times to combine, scraping down the sides of the bowl with a spatula as needed.
Step 4: While the food processor is running on a low setting (or using short pulses), slowly drizzle in the extra virgin olive oil in a steady stream. This helps emulsify the sauce and keeps the color vibrant.
Step 5: Stir in the salt, black pepper, and optional lemon juice. Taste and adjust seasoning if necessary.
Step 6: Transfer the pesto to a jar or airtight container. If not using immediately, pour a thin layer of olive oil over the top to prevent oxidation.