Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the softened cream cheese, sour cream, and mayonnaise.
Mix until the mixture is smooth and creamy.
Add the chopped spinach to the bowl and stir until well combined.
Incorporate the shredded cheese and grated Parmesan cheese into the mixture.
Season with garlic powder, onion powder, salt, and pepper. Adjust to taste.
Transfer the mixture into a baking dish or an oven-safe bowl.
Smooth the top with a spatula for even cooking.
Bake in the preheated oven for 20-25 minutes or until bubbly and golden on top.
Remove from the oven and let cool slightly before serving.