7 oz bittersweet chocolate, broken into pieces
1/2 cup warm water
3 large eggs, separated
3 tablespoons superfine sugar
6 ramekins, each with a capacity of 2/3 cup, or 6 individual serving glasses
a little whipped cream (optional)
First of all place the broken-up chocolate pieces and warm water in a large heatproof bowl, which should be placed over a saucepan of barely simmering water, making sure the bowl doesn't touch the water. Then, keeping the heat at its lowest, allow the chocolate to melt slowly - it should take about 6 minutes. Now, remove it from the heat and stir it until it is smooth and glossy; let the chocolate cool for 2-3 minutes before stirring in the egg yolks. Mix it well with a wooden spoon.
Next, in a clean bowl, whisk the egg whites to the soft-peak stage, then whisk in the sugar, about a third at a time; whisk again until the whites are glossy. Now, using a metal spoon, fold a tablespoon of the egg whites into the chocolate mixture to loosen it, then carefully fold in the rest. You need to have patience here - it needs gentle folding and cutting movements so that you retain all the precious air, which makes the mousse light. Next divide the mousse between the ramekins or glasses and chill for at least 2 hours, covered with plastic wrap. I think it's also good to serve the mousse with a dollop of softly whipped cream on top.