Instructions

1. Whisk the egg yolks and sugar in a medium stainless steel bowl until blended. Whisk in Marsala, 1/2 cup cream, and salt. Place the bowl over a large saucepan of simmering water (do not let the bottom of the bowl touch the water). Whisk constantly until the sauce is thick and a thermometer inserted into the sabayon registers 160°F to 170°F, about 15 minutes.
2. Remove the bowl from over the water. Add the chocolate morsels and whisk until they are melted and the sabayon is smooth and blended. (The sabayon can be made 1 hour ahead. Let stand at room temperature. Whisk before continuing.)
3. Whisk the remaining 1/3 cup cream and the mascarpone in another medium bowl until peaks form. Dice cake into small cubes. Place about 1/2 cup of the cake cubes into each of six 1 1/2- to 2-cup old-fashioned glasses or water goblets. Spoon 2 heaping tablespoons sabayon over the cake. Top with a spoonful of the mascarpone cream. Repeat the layering with cake, sabayon, and mascarpone cream.
4. To make the chocolate curls, stand the chocolate bar in a large measuring cup. Microwave on 50% power in 10-second intervals just until the chocolate feels a bit warm. Stand the chocolate bar upright and run a vegetable peeler down one narrow edge, creating off chocolate curls. Sprinkle the curls over each tiramisu and serve.