Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish with olive oil or butter.

In a large skillet over medium heat, brown 1 pound of ground beef and 1 finely diced onion for 5-7 minutes. Add 3 minced garlic cloves, 1 tsp salt, ½ tsp black pepper, and ½ tsp paprika, cooking for an additional 1-2 minutes.

Stir in a 10.5 oz can of cream of mushroom soup and 1 cup of milk into the skillet, mixing until smooth.

Layer half of the thinly sliced potatoes in the bottom of the greased baking dish.

Spoon half of the beef mixture over the potatoes and sprinkle with 1 cup of shredded cheddar cheese. Repeat the layering with the remaining ingredients.

Cover the baking dish with foil and bake for 60 minutes. Then remove the foil and bake uncovered for an additional 15-20 minutes until the cheese is bubbly and golden.

Let the casserole rest for 10 minutes before serving.