Preheat your oven to 375°F (190°C).

In a large skillet, add the ground hamburger meat and diced onion. Cook over medium heat until the meat is browned, about 5-7 minutes. Drain any excess fat.

In a large bowl, combine the cooked meat mixture with the cream of mushroom soup, milk, garlic powder, paprika, salt, and pepper.

In a greased 9x13 inch casserole dish, layer sliced potatoes at the bottom.

Pour half of the meat mixture over the potatoes, followed by another layer of potatoes, and repeat until all components are used, finishing with a final layer of potatoes.

Spread the shredded cheddar cheese evenly on top of the final potato layer. Optionally, sprinkle breadcrumbs over the cheese.

Cover the dish with aluminum foil and bake in the preheated oven for 40 minutes. Remove the foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden.

Allow the casserole to cool for about 10 minutes before serving.