Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish with cooking spray or olive oil.

In a large skillet, heat the olive oil over medium heat. Add the ground beef and cook until browned, breaking it apart with a spoon for about 5-7 minutes. Drain any excess fat if needed.

Add the chopped onion and minced garlic to the skillet. Sauté for another 3-4 minutes until the onion is soft and translucent.

Spread the cooked beef mixture evenly in the bottom of the prepared baking dish, then layer the thinly sliced potatoes on top.

Season the potatoes with salt, pepper, Italian seasoning, and paprika.

Sprinkle the shredded cheddar and grated Parmesan cheese evenly over the beef.

Pour the beef broth (or water) around the edges of the casserole to keep the potatoes moist. If you want extra creaminess, drizzle with milk.

Cover the casserole with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 15-20 minutes until the potatoes are tender and the cheese is bubbly and golden.

Garnish with fresh parsley if desired, and serve hot.