01 - Fill a medium saucepan with approximately 2 inches of water. Bring to a gentle simmer over medium heat, maintaining a low temperature throughout the cooking process.
02 - In a large heatproof bowl, whisk together the egg yolks and granulated sugar vigorously until the mixture becomes pale yellow and slightly thickened, approximately 2 minutes.
03 - Place the heatproof bowl over the simmering saucepan, ensuring the bottom of the bowl does not directly contact the water surface. This gentle, indirect heat prevents curdling.
04 - Slowly drizzle the Marsala wine into the egg mixture while whisking continuously to prevent the eggs from scrambling and ensure smooth incorporation.
05 - Maintain constant whisking motion for 8 to 10 minutes until the mixture triples in volume, becomes frothy, and thickens enough to form soft, velvety ribbons that briefly hold their shape on the surface.
06 - Remove the bowl from heat and portion the warm zabaglione into chilled dessert glasses or decorative bowls. The dessert is most enjoyable served warm while maintaining its airy texture.
07 - Top with fresh berries such as raspberries, strawberries, or blueberries. Accompany with crisp ladyfingers or almond biscotti for dipping, if desired.