beat the egg yolks and half the sugar with electric mixer on high speed until pale and creamy. Beat the egg whites and remaining sugar on high speed until soft peaks form. Fold the whites into the egg mixture. Fold in the whipped cream followed by the coffee mixture and chocolate.
To make the molds: take 12 espresso cups and place them on a tray. Using parchment paper, cut strips long enough to wrap around the cups with an overlap and tall enough to come over the top of the cup about 1 inch. Wrap the paper tightly around the cup and use a rubber band to keep it in place. Pour in the coffee mixture to just below the top of the paper and carefully set in the freezer overnight. When completely set, remove the rubber bands and carefully peel off the paper. Dust with cocoa powder just before serving.