The Meringue Discs: Separate the whites from the yolks of egg, sift the flour, sift the chocolate powder. Heat the oven to 225 degrees F. Grease and dust a cookie sheet with flour. Place a plain nozzle in a piping bag.
Make the meringues by whisking in a large bowl the whites of eggs until very stiff. Beat in the salt and water, and gradually start beating in the sugar little by little (if this is done too quickly the whites will lose their bulk and turn almost liquid). Fold in the last tablespoon of sugar. The mixture should now have a good gloss and be very "peaky". Now place the glistening white meringue mixture into the forcing bag and pipe it into two 9-inch circles (being the same diameter as the cake) on the cookie sheet and dust with the chocolate powder. The remaining mixture can then be piped into small animal shapes as decoration.
Place the meringue mixture immediately into the preheated oven (225 degrees F.) on the middle shelf and bake for 2 1/2 hours. When ready the discs and animals should lift easily from the baking sheet and have a hollow sound when gently tapped, these can be cooled on a wire rack until required. They can also be stored in an airtight tin for several days, should you want to prepare this dessert ahead of time.
Cream Filling: Whip the cream until stiff and divide the cream into 2 bowls.
The almonds can be placed on a cookie sheet and broiled until golden brown and cooled. The sponge cake can now be split in 2 and the base lightly soaked with rum.
Assembly: Place the base of the cake on a plate. Spread a little chestnut puree over this and then a good wallop of fresh cream from one bowl.
Pop the second layer of sponge cake on top and sprinkle with rum.
To the cream in the first bowl, add more of the chestnut puree and beat in very thoroughly. Blend together with rum. Scoop this on top of the cake.
Take one layer of the baked cooled meringue and place this on top.
From the second bowl, take the puree, whipped cream and spread a thick layer of this gently on top of the meringue disc.
Lower the second round of meringue on top. To the remainder of cream, add the last of the chestnut puree and spread this over the sides of the vacherin and a thin layer over the top, using a palette knife.
Gently press the flaked almonds over the sides. Decorate the top with meringue animals and dust with the chocolate powder.