Toast the pine nuts in a dry skillet for 2–3 minutes until golden and fragrant. Cool slightly. This step adds depth—trust the toasty magic.
In a blender or food processor, add basil, Parmesan, garlic, and cooled pine nuts. Pulse a few times to break things up.
With the machine running, slowly stream in the olive oil until the mixture is smooth and spreadable. If it’s too thick, add a splash more oil; if too thin, add a little more cheese.
Season with salt and pepper. Add a squeeze of lemon if you want the bright lift. Pulse once more to combine.
Scrape into a jar or bowl. Use immediately or store in the fridge with a thin layer of oil on top to keep it bold.