1. In top of double boiler or in large metal bowl over saucepan of hot water, without bowl touching water, whisk yolks and sugar until light, about 3 minutes. Continue whisking over heat until mixture falls in ribbons when whisk is lifted above bowl.
2. Whisk in vanilla, cocoa and salt. Whisk in mascarpone. Remove top of double boiler or bowl from hot water. Press waxed paper against surface of pudding. Refrigerate to chill, 1 hour.
3. Beat cream in small bowl until stiff peaks form. Fold into pudding. Makes 4 servings.