Crush the cashews well, and rinse if they are salted, to remove excess salt. Blend together the first seven ingredients well in a blender until smooth. (A small, high-powered blender like a Nutri-Bullet works well for this.)
Transfer the blended sauce to a pan and add the milk and basil. Heat over medium heat for about 15 minutes, stirring to blend ingredients.
While the sauce is heating, shred the mozzarella cheese. (Shredding your own will result in a creamier sauce than using pre-shredded!) When very hot, add the mozzarella and stir until smooth.
Serve hot on zoodles (spiralized zucchini), spaghetti squash, or other vegetables.
This sauce contains only a fraction of the calories, saturated fat and sodium of traditional or commercial Alfredo sauces!