Put the yolks of the eggs and sugar in a double saucepan, and whisk until thick and creamy. Whip the evaporated milk until thick, and add to the eggs and sugar. Melt the chocolate over very gentle heat, add to the egg and sugar mixture. Put the gelatine in the warm water and heat to dissolve; then stir it into the chocolate mixture. Whip up the egg whites stiffly and stir into the chocolate mixture. Put into the prepared soufflé case. When set, remove the paper carefully, and decorate the top with whipped cream.