Prepare the Potatoes: Peel and slice the potatoes into thin rounds. Boil them in salted water for about 10 minutes, until they are just tender but not fully cooked. Drain and set aside.

Cook the Minced Beef: Heat a tablespoon of oil in a large skillet over medium heat. Add the finely chopped onion and cook until softened (around 5 minutes).

Add the minced garlic and cook for another minute until fragrant.

Add the minced beef to the skillet and cook until browned (7-10 minutes). Season with salt, pepper, and spices such as paprika or cumin. Stir in the tomato sauce and sliced mushrooms, and cook for another 5 minutes.

Assemble the Casserole: Preheat the oven to 180°C (350°F).

In a greased baking dish, arrange half of the sliced potatoes in a single layer.

Spread the minced beef and mushroom mixture evenly over the potato layer.

Add the remaining potatoes on top and sprinkle the grated mozzarella cheese over the entire casserole.

Bake the Casserole: Place the assembled dish in the preheated oven and bake for 25-30 minutes, or until the cheese is melted, bubbly, and golden brown, and the potatoes are cooked through.

Prepare the Creamy Garlic Cucumber Sauce: While the casserole is baking, mix the sour cream, mayonnaise, minced garlic, chopped cucumber, and dill in a bowl.

Season the sauce with salt and black pepper to taste. Stir well and refrigerate until ready to serve.

Serve: Once the casserole is baked, let it cool slightly for about 5 minutes. Slice and serve with the creamy garlic cucumber sauce on the side for a fresh, tangy complement to the rich flavors of the casserole.