Crack the egg reserving the eggshell to use as a measure. Using an electric whisk, beat the egg yolk in a heatproof bowl with the sugar to make a smooth, soft cream. Add ½ eggshell (4 teaspoon) of Marsala for each egg yolk and place the bowl over a pan of simmering water (do not let the bowl touch the water), whisking continuously without letting the mixture reach the boil. After about 10 minutes when the mixture becomes thick and foamy the Zabaglione is ready. For a chilled version let the Zabaglione cool down, whisk the egg whites until stiff and add them to the Zabaglione. Pour in small moulds and refrigerate for 5/6 hours before serving. For a more delicate version use Moscato dAsti wine (in the same proportion) instead of Marsala wine.
These delicious recipes were created by Sandra et de Gemma Strocco, chefs of the starred restaurant Ca’ Vittoria, located in the romantic surroundings of Asti, Piedmont, where Saclà is based.