Before you bake them, store your soufflés in the refrigerator for a few hours (or for a few days in the freezer).
Mix the milk and starch, then bring them to the boil. Pour the milk over the melted chocolate and smooth the results out with a whisk. Beat the egg whites, adding in the sugar as soon as you start doing so to make sure you obtain a totally smooth mixture. Add some of the beaten egg whites to your first mixture, followed by the yolks. Finish off with the remaining egg whites. Pour your mixture into greased ramekins which you have sprinkled with sugar, then scrape off any excess from the surface.
BAKING: At 375°F (190°C) for 6-7 minutes, depending on the size.
The aim is for the soufflés to stay very soft in the middle.