In a medium saucepan, combine sugar, cornstarch and salt. Stir in whole milk. Stir over medium heat until mixture begins to simmer. In a small bowl, beat eggs. Stir about 1 cup hot milk mixture into beaten eggs. Stir egg mixture into remaining hot milk mixture. Cook and stir over low heat until slightly thickened, about 2 minutes. Stir in melted chocolate. Beat with a whisk until mixture is smooth. Stir in evaporated milk, whipping cream and vanilla. Cool to room temperature. Pour into ice cream canister. Freeze in ice cream maker according to manufacturer's directions. Makes 2 quarts.