Preheat the Oven: Begin by preheating your oven to 375°F (190°C) and grease a 9x9-inch baking dish with cooking spray.
Mix the Ingredients: In a large mixing bowl, combine the following ingredients: chopped spinach, chopped artichoke hearts, grated Parmesan cheese, mayonnaise, sour cream, shredded mozzarella cheese, softened cream cheese, minced garlic, salt, and black pepper. Use a whisk or an electric mixer to blend everything thoroughly until you have a creamy and well-mixed dip.
Transfer to the Baking Dish: Spoon the creamy mixture into the prepared baking dish, spreading it evenly.
Bake the Dip: Cover the dish with aluminum foil and place it in the preheated oven. Bake for approximately 25-30 minutes, or until the dip is hot and bubbly, and the top is golden brown.
Serve and Enjoy: Once baked to perfection, remove the dip from the oven, and let it cool slightly. Serve it warm with your favorite dippers, such as tortilla chips, pita bread, or vegetable sticks. Enjoy the creamy and savory goodness of this Spinach and Artichoke Dip!