Porrusalda

A traditional home dish of the Basque Country (Bizkaia, Gipuzkoa, Álava) and the neighboring north — Navarre and La Rioja — where farmhouse families (baserritarras) grew leeks in their kitchen gardens and stretched them with potatoes and a little salted fish through the winter and early spring, when leeks are at their best. It is peasant food with no fixed or dated origin; the exact origin is unrecorded. The Basque-language name porrusalda — porru (leek) plus salda (broth) — states the dish plainly, and the Basque porru itself descends from Latin porrum (leek). The salt-cod version is a potaje de vigilia, a meatless dish long eaten on the Fridays of Lent, when the Catholic prohibition on meat made desalted cod the standard protein.

A light, clean broth that tastes above all of sweet poached leek. The potatoes are soft and partly broken down, just enough to give the liquid a little body without making it heavy; the whole bowl is mild, comforting, and low in fat. The salt-cod version adds a gentle salinity and soft white flakes of fish, and the cod's gelatin gives the broth a faint richness. A raw thread of olive oil over the top at the table ties it together.

Leeks are gently sweated and simmered until their mild sweetness comes out into the broth. The potatoes carry the texture: they are added in chunks and broken with a twist of the knife rather than cut cleanly — a technique the Spanish call cascar or chascar — so the ragged torn faces leach far more starch than a clean slice would, lightly thickening the broth without any flour or roux. If salt cod is used, it is soaked in cold water in the refrigerator for 24 to 48 hours, with the water changed every several hours, to draw out the salt before it goes into the pot; this lets it season the broth gently rather than overwhelm it, and the cod's gelatin enriches the liquid. It is a simple soup, and that restraint is the point.