Preheat oven to 350F degrees and spray a 9x13 baking dish with cooking spray.
In a large bowl, mix together the cream cheese, ½ cup of shredded mozzarella, ¼ cup of the shredded parmesan cheese, sour cream, mayonnaise, spinach, artichoke, and minced garlic until well combined. Season to taste with salt and pepper.
Spread the mixture evenly into your prepared baking dish.
Sprinkle the remaining shredded cheese across the top of the mixture and bake in the oven for 25 minutes, or until the cheese is melted through and the top is a light golden brown.
Transfer to the broiler for 2-3 minutes to crisp the topping then remove and allow to cool for 5 minutes. Serve with your favorite chips, bread or veggie sticks for dipping!