How to make
Peel the potatoes and grate them on a coarse grater. If you see that there is a cloudy (from the starch) liquid at the bottom of the bowl, strain it.
Finely chop the spring onions and mix them with the grated potatoes. Mix the vegetable mixture with olive oil, a little salt and black pepper and pour about 2-3 cups of water.
Spread the mixture in a baking and put it in a preheated oven at 390°F (200 degrees) for 15 minutes, then take it out and crumble the white cheese inside and if necessary, a little more water, so that the potatoes do not burn and stick to the baking pan. You should not add too much the water, so that they do not become mushy.
Bake them for another 10 minutes and taste them - if the grated potatoes have become tender, not too soft, go to the next step.
Beat the eggs with two to three pinches of salt and mix them with the yogurt and milk. Thicken this mixture with about 4-5 tbsp. of flour and pour the gratin with it. Bake until a golden brown crust forms.
Grate the yellow cheese and sprinkle it on the dish. Place it back into the oven briefly until it melts and until it aquires an appetizing color.
Serve the baked gratin with grated potatoes warm, sprinkled with fresh parsley.
Enjoy your meal!