Cut the sponge cakes in half lengthways and spread 6 halves thickly with raspberry jam and 6 with apricot jam. Arrange them in a large glass or china bowl, jam sides upwards: they can be piled two or three deep. Among them put 18 or so ratafias or 3 or 4 macaroons broken up. Pour over the sherry and leave at least 20 minutes to soak.
Meanwhile whip the cream, sugar and brandy as for a s