Peel the potatoes and cut into bits. Cook for 10-15 minutes in salted water (check the progress with the tip of a sharp knife).
Meanwhile, cut the mushrooms and the Gyros into small bits.
Lightly fry the mushrooms in a how pan. Season with salt and pepper and add a splash of white wine. Let them cook for about a minute, then add the Gyros. Mix well and then place into an ovenproof dish.
Once the potatoes are done, pour away the water. Mash the potatoes up with 2 tbsp of olive oil, some grated nutmeg and some salt and pepper. Chop up the chives and fold into the mashed potato.
Cover the mushroom and Gyros mixture with the mashed potato. Sprinkle some yeast flakes over the dish and bake in the oven for 20 minutes (at 180° C).
A great side is a green salad!