Preheat oven to 350°F (175°C).
Sauté washed spinach in a skillet until wilted, then chop finely.
In a bowl, mix cream cheese and sour cream until smooth. Add shredded cheese, garlic powder, onion powder, salt, pepper, and fold in the chopped spinach.
Pour the mixture into a greased baking dish. Top with reserved shredded cheese.
Bake for 25–30 minutes until bubbly and golden brown.
