Prepare the Ground Beef Filling:Heat vegetable oil in a large skillet over medium heat. Add the ground beef and cook until browned, breaking it apart as it cooks. Once the meat starts to brown, add the chopped onion and stir until soft and translucent. Add the minced garlic and sauté for another minute until fragrant. Stir in the grated carrot, chopped bell pepper, and celery. Cook for about 5–7 minutes, stirring occasionally until the vegetables soften. Then, add the tomato paste, smoked paprika, cumin, and a pinch of salt. Mix everything well and cook for 3–4 more minutes on low heat. Finally, stir in the freshly chopped parsley for a burst of color and freshness. Set aside.

Make the Mashed Potatoes:Boil the peeled potato chunks in salted water until tender, about 15–20 minutes. Drain and mash them while hot until smooth. Add the eggs, dried herbs, and flour. Mix well until creamy and slightly thickened. The texture should be spreadable but firm enough to hold layers in the casserole.

Layer the Casserole:Preheat the oven to 180°C (350°F). Lightly grease your baking dish with vegetable oil. Spread a layer of mashed potatoes on the bottom — about half of the mixture. Then, spoon the ground beef and vegetable filling evenly on top. Finish with the remaining mashed potatoes, spreading them smoothly over the surface to create a uniform top.

Add the Cheese Topping:Generously sprinkle the grated mozzarella cheese over the top layer. Make sure the cheese covers the entire surface so it melts evenly and forms a golden crust.

Bake the Casserole:Place the dish in the preheated oven and bake for about 30 minutes or until the top is golden and bubbling. The edges should be slightly crisp, while the center stays creamy and soft. Let it rest for 5–10 minutes before serving to allow the layers to set.

Prepare the Fresh Vegetable Salad (Optional):In a large bowl, combine the shredded cabbage, tomato wedges, chopped cucumber, grated garlic, and green peas. In a small bowl, mix Greek yogurt and mustard to make a creamy dressing. Pour over the vegetables, add salt and pepper, and toss everything well. Serve alongside the casserole for a refreshing contrast.

Serve and Enjoy:Slice the casserole into portions and serve warm, paired with the fresh vegetable salad. Each bite offers a perfect blend of savory beef, creamy potatoes, and melty cheese — pure comfort on a plate.