Papas Arrugadas (Wrinkled Potatoes in Salt Crust)

Variations

• Papas bonitas: the Canary Islands' own landrace varieties (papa bonita, papa negra and others), old South American lines that are smaller, thicker-skinned and yellower-fleshed than mainland potatoes. Failing those, any small waxy potato.
• With seawater: the original method. Seawater is only about 3.5% salt, so it works because the water is never changed and is boiled down — the 150g per litre here is imitating that final concentration with tap water.
• Less salt: down to 100g per litre works, with shallower wrinkles and skins that are easier to eat. Below about 50g per litre you have made boiled potatoes.
• In the oven: 10 minutes at 200°C after boiling will also finish them. More even than the pan, but less salt settles.
• Without mojo: served plain beside grilled fish or meat.

Tips

• Go fifteen times past the number salt and seasoning gives and what the salt does inverts. That guide says blanching water "has to be salty for the seasoning to reach inside the ingredient — roughly 10g of salt per litre", and adds that "the water tasting salty and the finished dish tasting salty are separate questions." At 1% the brine is a medium that carries seasoning inward and stays behind in the pan. At 15% it is a drying agent: osmosis pulls water out of the potato through its skin, and once the water has boiled away the salt stays as crystals. Same substance, one order of magnitude, the opposite job.
• And what that guide files as an emergency measure is this recipe. Its first answer to an oversalted pot is "add a starchy or protein-rich mass — potato, tofu — and simmer. It absorbs salt." This dish does that deliberately and to the limit.
• The wrinkles are the skin shrinking onto shrunken flesh. Which is why peeling them gives you neither the wrinkles nor the crust: the skin is both the osmotic membrane and the finished surface.
• Use waxy potatoes. Mashed potatoes tells you to use starchy russets because it wants them to collapse and go fluffy. Here they have to survive twenty minutes in heavy brine and hold their shape, which is the opposite requirement.
• Do not rinse the starch off. Patatas bravas says to rinse the potatoes to wash off starch for a crisper exterior; here the whole point is not to disturb the skin at all.
• Do not walk away for the last 5–10 minutes. Left on the heat after the water has gone they simply scorch underneath; taken off early the surface is still wet, the salt is still dissolved in it, and no crystals form.
• Do not pour the sauce over. Mojo spooned on top dissolves the salt crust you spent ten minutes making. It goes out separately, to dip into.