For the jelly, whisk the yolks, cream, sugar, chocolate and cornflour together over a low heat, stirring constantly, until thick.
Mix rum with water and jam and heat slightly.dip biscuits in the rum and jam mixture. Place a layer, rum jam side up, in a salad bowl (15 cm Ø and 10 cm high) lined with foil, spread cream on top, alternate layers of dipped biscotti and cream on top and cover with foil.
Allow dome to chill for 2 hours. Turn out of mold and remove foil. Beat egg whites with sugar until stiff, spread on dome and bake at 200 degrees in preheated oven for 5 minutes until golden. Divide the jelly with a serrated knife.