In a mixing bowl, combine the chopped spinach, sour cream, mayonnaise, Parmesan cheese, mozzarella cheese, minced garlic, salt, and black pepper. Mix well.
Transfer the mixture to a baking dish and spread it out evenly.
Bake in the preheated oven for 20 minutes or until the top is golden and bubbly.
Remove from the oven and let it cool slightly before serving. Enjoy with chips, crackers, or bread.