Put the chestnuts in the food processor
with the sugar, then process until fairly
smooth. Put the butter and chocolate in a
pan with the milk, then gently heat, stirring,
until they have melted to a smooth sauce.
Stir in the vanilla and cognac. Add to the
chestnut mix in the food processor, then
whizz again until fairly smooth.
Line a lightly buttered small loaf tin with
cling film, then pour in the chestnut truffle
mix. Smooth the top, then cover the tin with
cling film. Chill for 24 hrs.
To serve, turn the truffle cake out onto
a flat plate or board. Peel off the cling film.
Gently melt the chocolate, butter and cream
for the topping, then spread over the top
and sides of the cake. Return to the fridge
to set. Will keep in the fridge for another
6 days. Decorate with a dusting of icing
sugar. Serve cut into thin slices with a little
single cream poured around (cold vanilla
custard is also very good).