The Truth about Turkey Day:It’s not what you were told. The American Thanksgiving Day ritual – with its Turkey, Cranberry Relish, and Sweet Potato Casserole studded with mini-marshmallows – is really the result of the fanciful imagination of magazine editors. There was no Pumpkin Pie at the Plymouth Plantation.Get used to it.It is a balmy and wet November evening in Manhattan, and I arrive at the