Preheat oven to 375°F (190°C).
Grease a baking dish lightly with cooking spray or butter.
Wash and thinly slice potatoes.
Heat olive oil in a skillet over medium heat.
Add diced onion and cook until softened.
Add ground beef and cook until browned. Drain excess grease if needed.
Season beef with garlic powder, onion powder, paprika, salt, and pepper.
In a bowl, whisk together cream of mushroom soup and milk until smooth.
Layer half the sliced potatoes into the baking dish.
Top with half the beef mixture.
Spoon some sauce over the layer and sprinkle with cheese.
Repeat layers with remaining potatoes, beef, sauce, and cheese.
Cover with foil and bake for 45 minutes.
Remove foil and bake another 15–20 minutes until potatoes are tender and cheese is golden and bubbly.
Let rest for 5 minutes before serving.