Get Ready: Preheat your oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish.
Creamy Base: In a large mixing bowl, combine the softened cream cheese, sour cream, heavy cream, mayonnaise, minced garlic, salt, and pepper. Whisk until everything is smooth and well blended.
Mix It All In: Add the shredded cooked chicken, the well-drained spinach, chopped artichoke hearts, and grated Parmesan cheese to the creamy mixture. Stir gently until all ingredients are evenly coated.
Bake Away: Pour the delicious mixture into your prepared baking dish. Spread it out evenly, then sprinkle the shredded mozzarella cheese generously over the top.
Golden Finish: Bake for 20 minutes at 375°F. Then, increase the oven temperature to 400°F (200°C) and bake for an additional 5 minutes, or until the mozzarella is beautifully golden and bubbly.
Serve & Enjoy: Let the casserole cool for a few minutes before serving. This hearty and healthy dish is perfect for a satisfying meal! Store any leftovers in an airtight container in the fridge for a few days or freeze for later.