Zabaglione - cooking recipe

Ingredients

8 large egg yolks
1 cup confectioners' sugar (powdered)
1/2 cup dry marsala (or Sherry)

Preparation

Place the egg yolks and the sugar in top of a double boiler and place on top of the bottom of the boiler.
The water should be lightly boiling and the should not be touching the bottom of the top of the boiler. (You can also use a bowl over a large pot of boiling water. ).
Use a wire whisk and whip the mixture until it is foamy. (I'm planing to use my electric mixer.).
Then add the Marsala and continue to cook the mixture until it has doubled in volume.
Use an instant-read thermometer to insure the mixture has reached 140 degrees. A MUST.
Beat the mixture for additional minute or two.
Serve the zabaglione immediately.
This dish looks quite elegant served in long stemmed wine or parfait glasses.
I see other recipes will use a savoiardi cookie for garnish.