1. In 2-quart saucepan, with wire whisk, mix sugar, cornstarch, cocoa and salt until combined. Whisk in milk until blended. 2. Heat mixture to boiling over medium heat, stirring constantly. Add chocolate, and cook 1 minute, stirring, until chocolate melts and pudding thickens slightly. Remove saucepan from heat; stir in vanilla. Spoon pudding into custard cups; serve warm. Or, cover surface of pudding directly with plastic wrap and refrigerate. Makes 4 servings.