Lupini beans are the flat, round, golden-yellow seeds of the white lupin (Lupinus albus), a Mediterranean legume eaten almost exclusively after a long debittering soak. Straight off the plant the seeds are punishingly bitter and laced with toxic alkaloids, so they are boiled and then steeped in repeated changes of water — and usually salty brine — for days to leach the bitterness away. The result is a firm, springy, savoury-salty snack with a slip-off skin, sold in jars and from market barrels across Italy, Portugal, Spain, Egypt and the Levant and eaten by the handful with an aperitivo. They are strikingly high in protein and fibre and very low in starch, but the debittering step is not optional: improperly soaked lupini can cause real alkaloid poisoning.