Carefully wash the strawberries and let them drip off on kitchen paper. Mix egg yolk, egg and sugar in a metal bowl until creamy. Add Marsala and whip until foamy on a hot water bath until the cream has about doubled in volume.
It is best to stir cold on a bowl of ice water. Put half of the zabaglione on 4 plates. Cut the strawberries in half or place them whole in the zabaglione. Using a peeler, grate shavings from the chocolate and sprinkle over the zabaglione.
Dust with icing sugar and cocoa and decorate with strawberry leaves. Add the rest of the zabaglione extra.