Boil the potatoes and grate them on a coarse grater. Lay half of them onto a buttered tray and salt.
On top, place the diced ham and sprinkle on the cheese. Arrange the remaining potatoes on top and salt them.
Sprinkle 2-3 tbsp of butter on top, pour on the eggs beaten with the yoghurt. Bake the dish in a strong oven until reddened.