Warm the eggs yolks and the sugar in a double boiler over a low heat, and then whip them with a wire whisk. Pour Marsala into the yolks, drop by drop, and keep beating.
The mixture will begin to foam and then swell into a light soft cream. Do not overcook or it will collapse.
Cinnamon and grated lemon rind may be added before pouring in the Marsala, and this liqueur in turn can be replaced with a high-quality white, sweet, dry or sparkling wine. Brandy or cherry brandy may also be added.