Worcestershire sauce is a thin, dark, fiercely savoury English condiment built on fermented anchovies, tamarind, molasses, vinegar, onion, garlic and spice. Almost black and barely thicker than water, it splashes a complex sweet-sour-umami depth into far more than it ever appears in — marinades and gravies, Welsh rarebit, the Bloody Mary and the Caesar dressing — and most of its power comes from a long, slow maturation in cask.