Toast the pine nuts: Heat a skillet over medium heat. Once hot, add the pine nuts and toss occasionally to prevent burning, until they are golden and release a nutty aroma, about 4 minutes.
Add the toasted pine nuts and garlic to a food processor and pulse repeatedly until you have a fine crumb (but not paste). Add the basil, half of the lemon zest, half of the lemon juice, salt, black pepper to taste, and nutritional yeast (if using). Blend until a paste forms, scraping down the sides as you go along. Push the paste into the middle of the food processor.
With the motor running, stream in the extra virgin olive oil to start to form a sauce. Scrape down the sides again, and stream in more oil as needed until you have a smooth yet thick texture. Taste for seasonings, adding more salt, lemon, garlic, or nutritional yeast as needed. If you’d like a smoother texture but have reached the right amount of oiliness, add a tablespoon of water and blend again.
Store in an airtight glass jar in the fridge for 5 days.