Today allegedly is <strong>National Mustard Day.</strong> I'm all for mustard. I don't think we use it nearly enough. Here in New Orleans, we're lucky enough to have a home-grown, unique variety of mustard that gives many of our dishes a distinctive flavor. One of the most ubiquitous sauces in Creole cookery--remoulade, in all its different colors and recipes--includes a good bit of Creole mustard. Mustard is made from the seeds of a member of the cabbage family native to Europe. The seeds contain oil, so when they're crushed they become a paste. When water is added, a sulfuric compound in the seeds reacts to give the sharply flavored mustard bite. It fades away unless something acidic (vinegar, usually) is added. Mustard has been used to flavor food in Europe since ancient times. Mustard seeds come in many colors, but yellow is not one of them. The yellow color in prepared mustards and Colman's dried mustard powder comes from the addition of turmeric. The plant that grows mustard seeds is also eaten as greens. But that's another flavor, another matter, for another day.