Preheat your oven to 350°F (175°C).

In a large skillet over medium heat, brown the ground beef along with the diced onion until the meat is fully browned and the onions are soft. Drain excess fat if necessary.

In a large mixing bowl, combine the browned beef and onions with cream of mushroom soup, milk, garlic powder, onion powder, salt, pepper, and paprika (if using). Stir until well mixed.

Grease a 9×13-inch baking dish. Spread half of the frozen hashbrowns across the bottom of the dish.

Pour half of the beef mixture over the hashbrowns, then sprinkle one cup of shredded cheddar cheese on top.

Add the remaining hashbrowns on top of the cheese layer, followed by the rest of the beef mixture. Finally, top with the remaining shredded cheddar cheese.

Dollop sour cream over the top if desired before baking.

Cover the casserole with aluminum foil and bake in the preheated oven for 30 minutes.

Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and golden brown.

Let the casserole cool for about 10 minutes before slicing to allow the layers to set up.

Garnish with fresh parsley if desired before serving.