01 -
Preheat the oven to 350°F (175°C).
02 -
In a large skillet, heat the olive oil or butter over medium heat. Add the diced onion and cook until softened (about 3-4 minutes). Add the ground beef and cook, breaking it up as it browns. Drain any excess fat, then season with garlic powder, onion powder, salt, and pepper.
03 -
In a large mixing bowl, combine the cream of mushroom soup, sour cream, milk, 1/2 cup of the shredded cheddar cheese, and the cooked beef mixture. Stir everything together until well mixed.
04 -
In a greased 9x13-inch baking dish, layer half of the sliced potatoes evenly on the bottom. Spoon half of the beef mixture on top. Repeat the layers, ending with the beef mixture.
05 -
Sprinkle the remaining 1/2 cup of shredded cheddar cheese over the top of the casserole.
06 -
Cover the casserole with aluminum foil and bake in the preheated oven for 40-45 minutes, or until the potatoes are tender when pierced with a fork.
07 -
Remove the foil and bake for an additional 5-10 minutes to let the cheese melt and the top become golden.
08 -
Let the casserole cool for a few minutes before serving. Garnish with chopped parsley if desired.