How to make
Wash the potatoes, put them in boiling water without boiling them, then cool, peel and cut them into plump circles. Grease a tray well and sprinkle breadcrumbs on its bottom.
Arrange the potatoes on top, and between the layers, sprinkle with salt, black pepper and nutmeg. For the topping, beat yoghurt and baking soda and add 1 egg, flour and a little salt to taste.
Pour this mixture over the potatoes and put the gratin to bake until it solidifies and gains a nice tan. Optionally while arranging the potatoes, you can sprinkle crumbled feta cheese between them.
Once the topping becomes solid, remove, sprinkle it with plenty of grated cheese and return it to toast again.
Serve the gratin with yoghurt slightly chilled.