Preheat your oven to 400°F. While it heats, line a 9x13 inch baking dish with foil and lightly coat it with nonstick cooking spray—this ensures easy cleanup and prevents sticking. Having your pan ready before mixing the hash browns helps the mixture cook evenly without sitting around.

In a large bowl, combine the frozen hash browns (no need to thaw), finely chopped onion, and shredded cheese. Add the garlic powder, salt, and black pepper to taste. Drizzle in the olive oil and melted butter, then stir everything together until the potatoes are evenly coated and the cheese is distributed throughout. I like to use my hands or a sturdy spoon to really work the mixture together—this helps the butter and oil coat every strand of potato for better browning.

Spread the hash brown mixture evenly onto your prepared pan, pressing it down gently with a spatula to create a compact, even layer. This helps the hash browns cook uniformly and develop crispy edges. Place in the preheated 400°F oven and bake for 28 minutes, or until the top is golden brown and the edges are crispy. For extra crispy edges, I sometimes give it a quick 2-3 minute broil at the end, watching carefully to avoid burning.

Remove the hash browns from the oven and let them rest for 2-3 minutes before serving. This brief rest allows the cheese to set slightly, making it easier to portion. Serve hot alongside bacon, eggs, or your favorite breakfast proteins.