Step 1Prepare a bowl of ice and water, one that is large enough for the bowl that you'll be cooking the sabayon in to nest inside.
Step 2Place a medium stainless steel bowl over a saucepan of simmering water. The bottom of the bowl should be 1 inch above the water so it gets warm.
Step 3Remove the bowl from the heat, add the yolks and the 1/2 cup sugar and whisk them together. Whisk in the wine. Set the bowl over the simmering water and continue whisking until the mixture becomes foamy and then thickens to a soft ribbon and reaches 165 to 175 degrees; this takes 7 to 10 minutes depending on the original temperature of the ingredients. Remove from heat and immediately float the bowl on the iced water. Stir occasionally until cool, 5 to 10 minutes.
Step 4In a separate bowl, whip the cream with the remaining 1 tablespoon of sugar until soft, then fold into the chilled sabayon mixture. Serve chilled.