Preheat your oven to 350°F. Line a 9x13" pan with foil and grease it. Set it aside.

In a large bowl, place the hashbrowns, condensed soup, sour cream, onion, seasonings and 1 1/2 cups of the cheese. Stir it all together until it's all well combined.

Pour the hashbrown mixture into the prepared baking dish and top it with the remaining 1/2 cup of cheese. Cover the baking dish with foil.

Bake covered For an initial 40 minutes. For the cornflake topping, if using, just combine the crushed cornflakes and melted butter in a bowl until combined and the cornflakes are all moistened.

After the initial 40 minutes, remove the foil from the top of the baking dish. If you're using the cornflake topping, then spread it over the top now. Return the dish to the oven and bake uncovered for an additional 15-20 minutes.

Let this stand for 5 or so minutes, then serve and enjoy. Store any leftovers in the fridge.

If making this ahead of time, do everything through step 3. But once you cover the dish, place it in the fridge. Once you're ready to bake it, take it out and let it sit for 20 or so minutes to bring it back closer to room temperature, then bake as directed.