In food processor or blender, blend all of the ingredients together.
Serve and enjoy!
Notes
If for any reason you're not feeling the pine nuts, you can easily swap those out for walnuts! They provide roughly the same consistency and nutty flavor that you've come to love from pesto sauce.
Make this recipe vegan by trading out the mozzarella out for vegan cheese. Still delicious and you won't even notice that it's vegan!
Dried basil works just fine in the recipe and can be used to add that delicious pesto flavor, although fresh basil will be just as good if not better. If you opt for fresh basil, simply reduce the amount of spinach so that your basil flavor can really shine through.