Step 1: Add the garlic cloves and pine nuts to the bowl of a food processor. Pulse several times until finely chopped. This ensures the garlic is evenly distributed and the pine nuts are broken down, releasing their oils.
Step 2: Add the fresh basil leaves to the food processor. Pulse again until the basil is coarsely chopped and combined with the garlic and pine nuts. Do not over-process at this stage, as you want to maintain some texture and prevent the basil from turning dark.
Step 3: Scrape down the sides of the food processor bowl with a spatula. Add the freshly grated Parmesan cheese and Pecorino Romano (if using). Pulse a few more times until everything is well combined.
Step 4: With the food processor running on low speed, slowly drizzle in the extra virgin olive oil in a steady stream. Continue processing until the pesto reaches your desired consistency – smooth but still with a slight texture is ideal. You might not need all the olive oil, or you might need a little more; adjust to your preference.
Step 5: Season the pesto recipe with salt and freshly ground black pepper to taste. Remember that the Parmesan cheese is already quite salty, so start with a small amount and adjust as needed. Pulse one last time to incorporate the seasonings.
Step 6: Taste and adjust any seasonings. If it tastes too bitter, a tiny pinch of sugar can help balance it, though a good quality basil and olive oil usually prevent this. For an extra bright kick, a squeeze of fresh lemon juice can be added, though it’s not traditional in all pesto recipe variations.
Step 7: Transfer your fresh pesto recipe to an airtight container. To prevent oxidation and keep its vibrant green color, pour a thin layer of olive oil over the top before sealing. This acts as a barrier from the air.