Step 1: Gather all your ingredients. Ensure your basil is washed and thoroughly dried. Lightly toast your pine nuts in a dry skillet over medium-low heat for 2-3 minutes until fragrant, if desired. Let them cool completely.
Step 2: In the bowl of a food processor, combine the fresh basil leaves, pine nuts, and garlic cloves. Pulse several times until roughly chopped. Scrape down the sides of the bowl as needed.
Step 3: Add the freshly grated Parmigiano-Reggiano cheese, salt, and black pepper. Pulse again until the mixture is finely chopped but not yet a paste.
Step 4: With the food processor running on low, slowly drizzle in the extra virgin olive oil through the feed tube until the mixture comes together into a smooth, thick paste. Be careful not to over-process; you want a rustic texture.
Step 5: Taste and adjust seasonings as needed. You might want more salt, pepper, or even a touch more cheese depending on your preference.
Step 6: Transfer the finished pesto to an airtight container. If not using immediately, pour a thin layer of olive oil over the surface to prevent oxidation. Store in the refrigerator for up to a week or freeze for several months.