Soak the grapes in brandy for an hour or so. Melt the chocolate in a bain-marie.
Beat the butter and sugar together until light and creamy, then add the egg yolks and the melted chocolate, beating in well. Stir in the whipped cream, then the grapes, brandy and biscuits. Whip the egg whites until stiff and fold them into the mixture, carefully amalgamating all together. Line a
To prepare the chocolate coating, melt the chocolate in a bain-marie and mix in the butter and rosewater. When the coating is cool enough for spreading, take the cake still in its tin, and coat the exposed surface. Return the cake to the refrigerator. When the coating has set firm, take the cake out of the fridge and turn it out onto a rotary cake table. Coat the top and sides with the remaining chocolate and return it to the fridge. Serve with fresh double cream.