Preheat your oven to 350°F (175°C).
In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes.
Add the ground beef to the skillet and cook until browned, breaking it apart with a spoon. Drain any excess fat.
In a large mixing bowl, combine the cream of mushroom soup, milk, garlic powder, salt, black pepper, and paprika. Mix well until all ingredients are combined.
In the casserole dish, layer half of the sliced potatoes evenly on the bottom. Follow this with half of the cooked ground beef mixture. Pour half of the soup mixture over the top.
Sprinkle half of the shredded cheddar cheese over the soup mixture.
Repeat the layers with the remaining potatoes, remaining ground beef mixture, remaining soup mixture, and finish with the remaining cheddar cheese on top.
Cover the casserole dish with aluminum foil and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden brown.
Remove from the oven and let it sit for about 5-10 minutes before serving.