In old New York at Christmastime, bakeries sold stacks of paper-wrapped and beribboned stollen, the beloved German holiday bread. When I serve samples of fresh-baked stollen at the bakery, the customers' faces light up with discovery. Once I served it and a customer asked what he was eating. "It's stollen," I said. With a straight face, he replied, "Well, you should give it back!" This recipe, inspired by pastry chef Dieter Schorner, is extraordinarily light and flavored with rum-scented raisins and other fruits and nuts.