01 - Preheat the oven to 375°F.
02 - In a large mixing bowl, combine cream cheese, sour cream, and mayonnaise until smooth.
03 - Stir in the mozzarella, Parmesan, garlic, salt, black pepper, and red pepper flakes if using.
04 - Fold in the chopped spinach and artichoke hearts until well mixed.
05 - Spread the mixture evenly into a 1.5-quart baking dish.
06 - Bake for 25 minutes, or until hot and bubbly and the top is lightly golden.
07 - Remove from the oven and let cool for 5 minutes before serving. Serve warm with toasted bread, crackers, or fresh vegetables.