Preheat your oven to 350°F (175°C).

In a large skillet, add the chopped spinach and sauté over medium heat for about 2-3 minutes.

In a mixing bowl, combine the softened cream cheese and mayonnaise until smooth.

To the cream cheese mixture, stir in the sour cream, cheddar cheese, Parmesan cheese, garlic, black pepper, salt, and red pepper flakes.

Fold the sautéed spinach into the cheese mixture until well combined.

Pour the mixture into a baking dish and spread it out evenly.

Bake in the preheated oven for 20 minutes, or until hot and bubbly.

Let it cool for a few minutes before serving.

Serve warm with tortilla chips, bread, or vegetable sticks.