Cook the pasta according to package instructions. Reserve 1/2 cup of pasta water, then drain and set aside.
In a food processor, combine kale, olive oil, walnuts, garlic, nutritional yeast, salt, and lemon juice.
Blend until smooth, adding reserved pasta water as needed to reach desired consistency.
Toss the cooked pasta with the kale pesto until evenly coated.
Serve warm, garnished with additional parmesan or nutritional yeast if desired.