Preheat the oven to 375°F (190°C). Grease a 9x13-inch baking dish.

Heat the olive oil in a large skillet over medium heat.

Add the ground beef and break it up with a spatula. Cook until browned, about 5 to 7 minutes.

Drain any excess fat from the skillet to prevent a greasy casserole.

Add chopped onion and minced garlic to the beef. Cook until the onion softens and turns translucent, about 3 to 4 minutes.

Season the mixture lightly with salt and pepper.

Spread the beef and onion evenly across the bottom of the prepared baking dish.

Arrange the thin potato slices in overlapping layers over the beef. Keep the slices uniform for even cooking.

Sprinkle the Italian seasoning over the potatoes and season again with salt and pepper.

Combine the shredded cheddar and grated Parmesan, then scatter the cheese evenly over the potatoes.

Pour the beef broth or water around the edges of the casserole.

Cover the dish tightly with foil and bake for 30 minutes.

Remove the foil and bake uncovered for another 15 to 20 minutes, or until the potatoes are tender and the cheese is bubbly and lightly browned.

Let the casserole rest for 5 minutes before slicing and serving.