Boil the potatoes in their skins in salted water until tender (about 25 minutes), peel them, mash with a potato masher and leave to cool until lukewarm.
Rub the flour and butter together until you have fine crumbs.
Add the salt and the mashed potato, then quickly knead into an even dough.
Roll it out into a rectangle and fold it in three, like puff pastry.
Rest it in the fridge for 30 minutes.
Repeat the rolling and folding twice more, resting for 30 minutes each time.
Finally roll it out 2 cm thick and cut out scones.
Brush the tops with beaten egg and score a criss-cross pattern if you like.
Bake in a preheated oven at 200 °C for 20 minutes until golden brown.
Based on: A jó házikonyha (a classic Hungarian cookbook), modernised. Calories and protein are estimated.