01 - Preheat the oven to 350°F.
02 - In a large bowl, combine cream cheese, sour cream, mayonnaise, mozzarella, Parmesan, garlic, salt, pepper, and nutmeg. Mix until smooth.
03 - Add the drained spinach and mix thoroughly until well combined.
04 - Spoon the mixture into the hollowed-out sourdough loaf or a small baking dish.
05 - Place loaf or dish on a baking tray. Bake for 20–25 minutes, or until the dip is bubbling and golden on top.
06 - Serve hot, garnished with fresh herbs if desired. Use sourdough bread pieces for dipping.