Put all of your ingredients into the blender, and puree until smooth. You can add water 1 tablespoon at a time, as needed, to get things moving.
Adjust the salt and pepper, if necessary.
To make this recipe nut free, use pumpkin seeds or sunflower seeds instead of cashews.The final amount of water you'll need depends on the consistency you want and the size of your avocado. A large avocado might need more water to reach that creamy, pesto consistency you're looking for. You may need more water if you use the optional nutritional yeast, as well, since that can thicken up sauces.The nutritional yeast is optional and gives this pesto the cheesiness that you'd normally get from Parmesan.