Yucatecan Pickled Red Onions (Escabeche De Cebolla)

Red onions soak up the flavors of oregano and cumin in this classic pickle relish, served with fresh seafood in Yucatan, Mexico.

Correction: October 26, 2011 — An earlier version of this recipe stated that the vinegar should cool to room temperature. However, because the liquid is not heated, we have removed that instruction.