½ cup freshly grated Parmigiano Reggiano, best you can afford (and wait to grate!)
Pepper to taste
Pick your basil leaves and wash them well. You can harvest a basil plant at any point in its life, just be sure not to ever take more than ⅓ of the plant. The size of leaves does not matter. Most harvest from the top, but you can harvest from anywhere.
Toast the pine nuts for a richer flavor. Just add to a sauté pan over medium-low heat and they will start to turn a light brown and release an aroma after 2–3 minutes. Set aside to cool. (While cooling, grate the cheese.)
Add basil, toasted pine nuts, garlic, and salt to the bowl of the food processor. Pulse to uniform consistency, scraping down sides as needed. Can also do this by hand, using a mortar and pestle.
With machine running, drizzle in the oil in a steady stream. Scrape down sides as needed. How much oil to use depends on how thick you like your pesto.
Transfer to a bowl and stir in cheese. Note: if you are freezing the pesto, don’t add the cheese—do that after you defrost and are ready to use. Add pepper to taste.
Serve immediately in pasta, on pizza, as a dip or a dollop on anything (seafood, vegetables, potatoes, a baguette). Will keep in refrigerator for up to 1 week, and best to cover with a thin layer of oil to prevent browning.