Toast pine nuts in a frying pan, stirring occasionally, until golden brown, 5–7 minutes.
Keep a very close eye on them, as they will burn quickly when not watched.
Transfer to a food processor and let cool.
Add parmesan cheese and garlic, and pulse until finely ground, about 1 minute.
Add basil and place the top back on.
With the motor running, drizzle oil in a slow stream until pesto is mostly smooth, with just a few flecks of green, about 1 minute.
Season with salt.
Notes
Do Ahead: Pesto can be made 1 day ahead. Top with a layer of oil to prevent browning. Cover with plastic wrap, pressing directly onto the surface, and chill. You can also freeze in ice cube trays, and once frozen, store in a ziplock bag.