Preheat the oven to 375°F (190°C) and grease a 9×13-inch baking dish.

In a skillet over medium heat, brown the ground beef, breaking it up as it cooks.

Once the beef is browned, add the finely chopped onion and minced garlic, seasoning with salt, pepper, and paprika. Cook until the onion is softened.

In a separate bowl, combine the cream of mushroom soup and milk, whisking until smooth.

Begin layering the casserole: Place half of the sliced potatoes in the bottom of the dish, followed by half the cooked beef mixture, and finally half of the sauce. Repeat these layers one more time.

Cover the dish with foil and bake for 45 minutes.

Remove the foil, sprinkle the cheese on top, and bake for an additional 15-20 minutes, or until the casserole is bubbly and golden.