Preheat oven to 375°F (190°C) and grease a baking dish with butter.
In a large bowl, combine Alfredo sauce, cream cheese, sour cream, and garlic. Mix until smooth.
Stir in spinach, artichokes, salt & black pepper, and red pepper flakes.
Fold in mozzarella cheese and Parmesan cheese.
Transfer mixture to the baking dish and spread evenly.
Bake for 20-25 minutes until bubbly and golden on top.
Serve hot with tortilla chips, baguette slices, or vegetable sticks.