01 - Preheat the oven to 375°F. Lightly grease a 1–1.5 quart baking dish with butter or cooking spray.
02 - In a large mixing bowl, combine cream cheese, sour cream, and mayonnaise. Beat with a hand mixer or sturdy spoon until completely smooth and creamy.
03 - Stir in mozzarella, Parmesan, garlic, salt, pepper, and red pepper flakes until thoroughly incorporated.
04 - Gently fold in chopped artichoke hearts and spinach until evenly distributed throughout the cheese mixture.
05 - Spread the mixture into the prepared baking dish and smooth the top with a spatula for even baking.
06 - Bake for 20–25 minutes, or until the dip is bubbly around the edges and lightly golden on top.
07 - Serve immediately while hot, accompanied by tortilla chips, baguette slices, or fresh vegetable sticks.