Preheat your oven to 375°F (190°C).
In a large mixing bowl, combine the frozen shredded hashbrowns, cheddar cheese, sour cream, chopped onion, garlic powder, salt, black pepper, and melted butter. Mix thoroughly until all ingredients are well combined.
Transfer the mixture into a greased 9x13-inch baking dish, spreading it out evenly.
Bake in the preheated oven for 30-45 minutes, or until the top is golden brown and bubbly.
Remove from the oven and let it cool for a few minutes before serving.
Optionally, add an extra cup of cheese on top before baking for a cheesier dish.
For extra spice, add diced jalapeños or red pepper flakes.
If preparing ahead of time, store in the refrigerator before baking and adjust the cooking time as necessary.