Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the cream cheese, sour cream, and mayonnaise until smooth.
Add the chopped artichoke hearts and thawed spinach to the mixture.
Stir in the shredded mozzarella and grated Parmesan cheese.
Mix in the minced garlic, salt, black pepper, and red pepper flakes.
Transfer the mixture to a baking dish and spread it evenly.
Bake in the preheated oven for 20-25 minutes until bubbly and golden on top.
Remove from the oven and let it cool slightly.
Serve warm with tortilla chips, bread, or vegetable sticks.
Enjoy your delicious spinach artichoke dip!