4 egg yolks
1/2 cup (100 g) sugar
1/2 cup (120 cc) Marsala wine (if unavailable, substitute with Port or Madeira)

Beat the egg yolks in a double boiler until fluffy. If you don’t have a double boiler, use a heatproof bowl over a pan of simmering water.
Beat in the sugar  and the Marsala wine.
Whisk over simmering water, until the cream thickens just below boiling point when small bubbles appear.
Cool the zabaglione to room temperature, stirring occasionally to avoid the formation of a thicker layer. Transfer to individual serving bowls or glasses, decorate with whipped cream or chocolate shavings, and serve with cookies and a small glass of sweet Marsala wine.