Despite the title, this recipe doesn't actually come from New Orleans, but is named in honour of the wonderful pecan trees I admired on a visit there eons ago. I've been making this, or a version of it, for so long, and the name just stuck. The dressing is light as I don't like a coleslaw that is drenched in mayo, and the buttermilk makes it even lighter, though you can use yoghurt in its place. And please read the Additional Information section at the end of the recipe before proceeding.