Preheat the oven to 375F
Spray the baking dish with cooking spray
Add the cream cheese, butter, and milk to the baking dish
Put the baking dish into the preheated oven and bake for 10 minutes
Remove the baking dish from the oven
Stir the mixture in the baking dish until the ingredients are blended
Add the corn, black pepper, garlic, onion powder, cheddar cheese, and mozzarella cheese to the baking dish
Stir until all the ingredients are blended
Return the baking dish to the oven and bake for an additional 20 minutes