Make the potatoes as cooked, peeled potatoes, peel them and mash them with a potato masher in a wide bowl.
Melt the kuzu in the mineral water and mix well with all the other ingredients. Grease a shallow baking dish with butter and pour in the dough.
Bake at 160 °C in a convection oven for about 100 minutes. To keep the bread moist, place a baking dish with water on the bottom of the stove.
It tastes best if you cut it a day later.
To store it, put it in the refrigerator, where it will keep for 5-6 days.