5 ounces bittersweet chocolate, cut into small chunks
2 egg yolks
8 egg whites
Preheat the oven to 375 degrees.
Brush the inside of the soufflé dishes with soft butter. Lightly sprinkle with sugar and rotate the dish so the sugar evenly coats the surface.
In a mixing bowl, whisk the egg yolks and sugar until light and creamy. Add the flour and vanilla. Mix well.
Gradually whisk the scalded milk over the egg yolk mixture, and whisk well to blend. Transfer to saucepan. Whisk over medium heat until mixture thickens and comes to boil, about 5 minutes. Boil 1 minute. Pour into medium bowl. Stir in the chocolate and egg yolks. Press plastic onto surface of pastry cream.
Beat the egg whites with the cream of tartar until stiff.
Fold egg whites into custard mixture.
Spoon the the mixture into the two prepared molds or the small molds.
Bake 20 to 25 minutes for the 6-cup soufflés or 12 to 16 minutes for the small soufflés. Sprinkle with confectioners' sugar before serving.