01 - Preheat your oven to 375°F.
02 - In a spacious mixing bowl, thoroughly combine the softened cream cheese, sour cream, and mayonnaise until the mixture is smooth and lump-free.
03 - Add the well-drained spinach, chopped artichokes, minced garlic, both mozzarella and Parmesan cheeses, salt, pepper, and optional red pepper flakes to the cream cheese mixture. Stir gently until all components are evenly distributed.
04 - Carefully transfer the prepared dip mixture into a 1-quart baking dish and spread it into an even layer.
05 - Bake for 20 to 25 minutes, or until the dip is heated through, visibly bubbling, and its surface achieves a light golden hue.
06 - Allow the baked dip to cool for 5 minutes before serving. Present it warm with your preferred accompaniments such as tortilla chips, toasted baguette slices, or fresh vegetable sticks.