01 - Preheat oven to 375°F.
02 - In a medium skillet over medium heat, add the spinach (if using fresh) and cook until wilted, about 2–3 minutes. Remove from heat and roughly chop. If using frozen spinach, ensure it is thoroughly thawed and squeezed dry.
03 - In a large mixing bowl, combine cream cheese, sour cream, and mayonnaise. Beat until smooth.
04 - Stir in mozzarella, Parmesan, garlic, chopped artichokes, and spinach. Season with salt, black pepper, and red pepper flakes (if using). Mix until well combined.
05 - Transfer the mixture to a 1-quart baking dish and smooth the top.
06 - Bake for 20–25 minutes, or until hot and bubbling, and the top is lightly golden.
07 - Let cool for 5 minutes before serving. Serve warm with tortilla chips, sliced baguette, or vegetable sticks.