If you like regular zabaglione, you're going to absolutely love the frozen version. Above and beyond the flavor, you're going to see what might be the best way to make ice cream without an ice cream maker. Quite often, frozen desserts that aren't made with a machine can have a weird, icy, crystallized texture, but not here. This stuff is incredibly smooth and creamy. Serve with fresh fruit.
Although I prefer using a dry Marsala, you can use any dessert wine of your choice.
Most recipes for frozen zabaglione call for twice as much heavy cream, but this version reduces that for a much more intense, and authentic, zabaglione flavor. If you want, you can double the cream, or use 1 1/2 cups, to produce something less like frozen zabaglione, and more like zabaglione-flavored ice cream. The procedure is the same no matter the amount of heavy cream used.