Certainly descended from the Italian zabaglione, the Viennese version is different from its ancestor in many ways. Weinchaudeau is always made from a fruity white wine, not Marsala. And while zabaglione uses egg yolks only, Weinchaudeau includes a whole egg to give the froth a lighter consistency. Otherwise the cooking procedure remains the same, requiring constant whisking over simmering water and immediate serving. It’s imperative that the ingredients be at room temperature before you begin. Weinchaudeau is a popular sauce for strudel, especially for the grape and hazelnut version.