How to cook
Mix the yoghurt and mayonnaise. Put some of this sauce on the bottom of a deep bowl.
Grate the potatoes. Cover them with the sauce.
Grate on a layer of feta cheese. Add a layer of grated eggs. Pour in sauce.
Alternate the ingredients in this order until you run out. Pour on sauce at the very top and grate the remaining boiled eggs.
Garnish with olives.