Cook the pasta in salted water according to the instructions on the packet. Meanwhile, finely puree the pulp of the avocado with spinach, basil, garlic, pecans, lemon juice, parmesan and about half a cup of the pasta cooking water.
Add more cooking water depending on the desired consistency of the sauce. Season to taste with salt and pepper.
Drain the pasta, mix with the avocado sauce and serve immediately.