Rinse and dry basil: Wash leaves and spin them very dry. Water dulls flavor and thins the sauce.
Toast the nuts (optional): Lightly toast over medium heat until fragrant, 3–4 minutes. Cool completely for the smoothest blend.
Add nuts/seeds, garlic, and salt to a food processor. Pulse until finely chopped.
Add basil, nutritional yeast, and lemon juice. Pulse to combine.
With the machine running, slowly stream in olive oil until the pesto looks creamy and spoonable.
Taste and adjust: more salt, pepper, or lemon as needed. For a looser sauce, add a tablespoon of cold water or more oil.
Pasta: Toss with hot, just-drained pasta and a splash of pasta water to help it cling.
Veggies and grains: Spoon over roasted tomatoes, grilled zucchini, quinoa, or farro.
Sandwiches and bowls: Use as a spread for toast, wraps, and grain bowls.
