Step 1: Prep the Chicken - Preheat your oven to 375°F (190°C). Pound the chicken breasts to an even thickness of about 1/2 inch.
Step 2: Make the Spinach Artichoke Mixture - In a mixing bowl, combine the chopped spinach, marinated artichoke hearts, grated Parmesan cheese, mayonnaise, sour cream, and minced garlic. Season with salt and pepper to taste. Stir until well combined and set aside.
Step 3: Assemble the Dish - In a baking dish, arrange the pounded chicken breasts in a single layer. Spoon the creamy spinach and artichoke mixture evenly over each piece of chicken.
Step 4: Add the Cheese - Top each chicken breast with a slice of mozzarella cheese.
Step 5: Bake - Place the baking dish in the oven and bake for about 25-30 minutes, until cooked through and the cheese is bubbly and golden.
Step 6: Serve and Enjoy - Let the dish rest for a few minutes before serving.