Pickled red onions are thinly sliced red onions cured in a vinegar-based brine, usually with salt and a touch of sugar, until they soften slightly and turn a vivid pink. The acid mellows the onion's sharp bite while keeping its crunch, producing a tangy, faintly sweet condiment. They are closely associated with Mexican and other Latin American and Caribbean cooking, where they top tacos, tostadas, and grilled meats, but the technique itself is simple enough that quick-pickled onions (ready in 30 minutes to a few hours) appear across many cuisines as a topping for sandwiches, burgers, and salads. Common additions to the brine include cumin, oregano, citrus, or chili.