In a mixing bowl, combine the chopped spinach, sour cream, mayonnaise, grated Parmesan cheese, shredded mozzarella cheese, minced garlic, salt, and black pepper. Mix well.
Transfer the mixture to a baking dish and spread it 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, bread, or veggies.
Notes:
This spinach dip is best served warm and can be made ahead of time and reheated.