Wash the potatoes, peel them and put them to boil until semi-cooked, let them remain slightly stiff. Cut the ready potatoes into pieces, transfer them to a large bowl and add the coarsely grated feta cheese, beaten eggs, spices and chopped leeks or green onions and mix well.
Heat a tray in a preheated oven, melt the butter and pour in the potato mixture. Bake the dish for about 30 minutes at 392°F (200 °C) until tender.
Before removing from the oven, sprinkle with grated cheese and bake for another 2 minutes.