Preheat the oven to 350°F (175°C). Gather ingredients and a large mixing bowl.

In a large bowl, combine frozen hashbrowns, cream of chicken soup, sour cream, shredded cheese, chopped onion, garlic powder, salt, and pepper until well blended.

Grease a 9x13 inch baking dish with butter. Transfer the mixture into the prepared dish and smooth the top.

Sprinkle remaining shredded cheese over the top, then drizzle melted butter over the cheese layer.

Bake in the preheated oven for 45-50 minutes until bubbly and golden brown.

Remove from the oven and let cool for about 5 minutes before serving.