Cook your linguine per the package instructions, and reserve about one cup of the starchy cooking water before draining.
While your linguine is cooking, add your spinach, garlic and yeast to the cup of your food processor. Pulse until finely chopped, and start streaming in your lemon juice and oil (or water). Give it a taste, and season with salt and pepper. The flavor may come off a bit strong, but it will become more mild once you toss it with the pasta.
Drain your pasta once it’s cooked, and add your pesto to the hot pan, off the heat. Stir for about one minute, add your pasta, and toss until well coated with your pesto. If you’d like you can garnish with a pinch of nutritional yeast and some lemon zest. Serve with a nice side salad, and enjoy!