Bring about 1 or 1 1⁄2 inches of water to a boil in a medium saucepan. 

In the meantime, in a stainless or glass bowl, beat the yolks with the sugar and salt, using a manual or electric whisk, until they are pale and frothy (about 5 minutes). 

Slowly and gradually pour in the wine, whisking constantly. 

Lower the heat to the minimum setting so that the water barely simmers, and place the bowl with the eggs on top of the saucepan (the bottom should not touch the water). 

Keep whisking on top of the double boiler until the zabaglione is thick like a pudding, frothy, and “holds a ribbon.” This means that when you remove the mixer from the bowl, the zabaglione will fall in a ribbon-like pattern when drizzled over the bowl. 

Spoon into cups with the fruit or cookies, and serve. You can also keep warm by leaving it in the double boiler (heat off, or on top of a buffet warmer on the lowest setting) or chill it, but in either case you will need to cover it and stir occasionally in order to prevent the top from hardening into a “film.”