From the flour, salt, icing sugar, dissolved yeast and eggs, work a pastry-like dough by continuous slapping and folding until it becomes bubbly (if it turns out firmer than regular pastry dough, add a little more lukewarm milk).
Once the dough is nice and smooth, add the soft butter little by little.
Put it in a bowl and let it rest overnight in the fridge (or a cold place).
The next day, shape it as desired, or put it in one piece into a buttered tin.
Let it rise, then bake for 30-45 minutes depending on its size.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.