There are many ways to "wrinkle" potatoes. The method we explain here is one of the simplest, most efficient and widely used. Preparation: Put the unpeeled potatoes in a large, deep pan and fill with enough water to cover them (seawater is even better). For every kilogram of potatoes add a quarter of a kilogram of salt - it doesn't matter if you put in more, as the potatoes absorb only what is necessary. Put the pan on the flame and cover it with a clean cloth or wrapping paper on top of which the lid is placed.
Wait while the potatoes boil for between twenty minutes and half an hour, time enough for them to soften. Then pour away the water and drain the potatoes well. Without taking them out of the pan throw another handful of salt over them and dry them on a low flame while shaking them inside the pot for a short time (usually just under a minute).