1. Make an ice bath by adding ice to a large bowl so it’s half-full with ice, and add a small amount of cold water.
2. In a large heatproof bowl, whisk together the egg yolks, wine, and sugar. Set the bowl over a saucepan of water that’s at a low boil and vigorously whisk the mixture. (You can also use a hand-held electric mixer.) It will become frothy, and after a few minutes, will start to thicken. It may take up to 8 minutes to reach the point where it’s done. It’s ready when you lift the whisk and the zabaglione holds its shape on the surface of the sauce in the bowl for a few seconds. Do not overcook it.
3. Remove the bowl from the heat and place the bowl in the ice bath. Gently stir the mixture over the ice bath infrequently to cool the zabaglione. (It may deflate a bit, which is normal.)
4. When at room temperature, fold in the whipped cream and the lemon juice. Transfer the mixture to a shallow container and put in the freezer, covered, for at least eight hours.