Boil the potatoes in salted water, peel and mash them. Mash with a hand blender and add the butter, salt to taste, beaten eggs and slightly heated milk, stir well. Add the coarsely chopped spinach and stir again.
In a pan, heat up the oil, add the finely chopped onions and braise until softened. Add the mince and braise until it changes color slightly, sprinkle with the universal spice and stir. Remove from the heat.
Distribute half the mashed potatoes in a tray and sprinkle with a bit of black pepper. On top, distribute the filling evenly and remaining mashed potatoes, sprinkle with a little black pepper again. Pour the cream over the casserole and sprinkle with the grated cheese.
Bake in a preheated 392°F (200 °C) oven to a golden crust.