Preheat oven to 350°F (175°C). Lightly grease a 9×13-inch baking dish.
In a skillet over medium heat, cook ground beef until browned. Add onion, salt, pepper, garlic powder, and paprika. Cook until onions are soft. Drain excess fat.
In a small bowl, whisk condensed soup and milk until smooth.
Layer half of the sliced potatoes evenly in the baking dish.
Spread half of the beef mixture over the potatoes.
Spoon half of the creamy mixture over the beef, then sprinkle with cheese.
Repeat layers, finishing with cheese on top.
Cover tightly with foil and bake for 45–50 minutes.
Remove foil and bake uncovered for 10–15 minutes until cheese is bubbly and lightly golden.
Let rest for 10 minutes before serving.