Bring a large pot of water to a boil. Cook pasta according to package directions. Drain water and set aside.
In a large food processor, combine the basil, spinach, avocado, minced garlic, olive oil, parmesan cheese, lemon juice, salt (if using) and black pepper.
Pulse until pureed and no large chunks remain.
Add the avocado pesto puree to the pasta. Mix until evenly combined. You may wish to add a tablespoon or so of warm water to thin out the sauce slightly to make it easier to mix. Serve warm.
