Cook the pasta according to the package instructions. Reserve 1 cup of pasta water.
Add the avocado, basil, spinach, garlic, lemon juice, cheese and salt to a food processor or blender and puree until smooth. With the blender running, stream in the olive oil until incorporated.6
Pour the sauce over the pasta and toss to coat. Add some of the pasta water as needed to thin out the sauce to desired consistency. Season the pasta with salt and pepper to taste.