Sieve the chestnut puree and stir until
smooth, then divide in half. Mix one half with the egg yolks, vanilla
essence, cinnamon and 50 g/2 oz of the icing sugar. Whisk the egg
whites until stiff, then gradually whisk in 175 g/6 oz/ 1 cup of the
icing sugar until the mixture forms stiff peaks. Fold into the egg
yolk and chestnut mixture. Fold in the flour and spoon into a greased
and lined 25 cm/10 in cake tin (pan). Bake in a preheated oven at
180°C/350°F/gas mark 4 for 45 minutes until springy to the touch.
Leave to cool, then cover and leave overnight.
Sprinkle the gelatine over the water in a bowl and leave until spongy.
Stand the bowl in a pan of hot water and leave until dissolved. Leave
to cool slightly. Mix the remaining chestnut puree with the remaining
icing sugar and the rum. Whip the cream until stiff, then fold into
the puree with the dissolved gelatine. Cut the cake horizontally into
three and sandwich together with the chestnut puree. Trim the edges,
then chill for 30 minutes.
Boil the jam with the water until well blended, then brush over the
top and sides of the cake. Melt the chocolate in a heatproof bowl set
over a pan of gently simmering water. Shape the almond paste into 16
chestnut shapes. Dip the base into the melted chocolate, then into the
pistachio nuts. Spread the remaining chocolate over the top and sides
of the cake and smooth the surface with a palette knife. Arrange the
almond-paste chestnuts round the edge while the chocolate is still
warm, and mark into 16 slices. Leave to cool and set.