Wash the potatoes and cook them with the peel in boiling water for about 40 minutes. Once cooked, let them cool slightly and then peel them. Pass the fermentino and the potatoes in a potato masher, mixing and adding nutmeg, salt and pepper. Let the dough rest in the fridge for about twenty minutes, covering it with cling film. Then form the croquettes and bread them with the gluten-free grated bread. Put the frying oil in a pan and bring it to a boil. Then add the croquettes and wait until they become perfectly browned. Alternatively, the croquettes can be arranged in a bowl and cooked in a preheated oven for 15 minutes at 170°C.