Chop chocolate for the sorbet. Simmer 150 g sugar, cocoa and 450 ml water in a pot over medium heat for about 5 minutes, stirring frequently. Remove the pot from the stove. Add espresso and chocolate to the pot and melt, stirring from time to time.
Fill about half of the sorbet mass into four small glasses or espresso cups to ¾, the rest of the sorbet also into glasses or into an empty clean ice container. Cover and freeze for about 3 hours.
Just before serving for the zabaglione, beat the egg yolks, 25 g sugar and wine in a mixing bowl in a hot water bath with the whisks of the mixer for 6-8 minutes until a white and thick cream.
Arrange the zabaglione hot or cold on the chocolate sorbet as desired. Serve with fruit skewers, e.g. with pieces of peach.