Pickled Red Onions

I was introduced to these vividly pink onions while visiting the Yucatan Peninsula, where they are often served on cochinita pibil, the stupendous banana leaf–wrapped marinated barbecue pork dish of the region. They’re also boffo on top of tacos, salads, nachos, as a garnish for steak or bowls of beans, scrambled eggs, burgers…I can’t think of any dish I don’t like them on except maybe breakfast cereal. They keep indefinitely in the refrigerator and they’re a snap to make.