For the chocolate chestnut cake
225g bitter chocolate
225g unsalted butter
6 medium free-range eggs, separated
100g caster sugar
50g ground almonds
50g chestnut flour
1tsp baking powder
For the chestnut mousse
225g unsweetened chestnut purée
Seeds from one vanilla pod
170g mascarpone cheese
2tbs dark rum
250ml double cream
3 medium free-range egg whites
125g caster sugar
2 leaves of gelatine, soaked and melted
For the cocoa ganache
200ml cold water
200ml double cream
200g caster sugar
80g bitter cocoa powder
4 leaves of gelatine, soaked
For the candied chestnuts
200g fresh roasted and peeled chestnuts
200g caster sugar
1tsp unsalted butter
For the cocoa filo wavers
50g unsalted butter, melted
15g dark brown sugar
20g bitter cocoa powder
2 sheets of filo pastry
Preheat the oven to 180˚C and line a 1/2 gastronorm tray, 32cm x 26cm.
Melt the chocolate and butter over a double boiler, remove from the heat and whisk in the egg yolks.
While the chocolate is melting, whip the egg whites and sugar to a glossy meringue with soft peaks.
Fold the meringue into the melted chocolate mixture, sift over the chestnut flour, baking powder and ground almonds and fold it together.
Pour the cake batter into the prepared cake tin and bake for 20 to 22 minutes. Test with a metal skewer - if it comes out clean then the cake is cooked. Leave the cake on a cooling rack.
Once cooled, break the cake into pieces and dry it in the oven at 100°C until the texture of dried breadcrumbs.
To make the chestnut mousse, blend the chestnut purée and vanilla seeds till smooth, mix in the mascarpone and rum, and keep refrigerated until the rest of the ingredients are ready.
Whip the cream to a light ribbon stage. Whip the egg whites and sugar over a pan with boiling water until it starts to foam and has nearly doubled in size. Transfer to a mixer with a balloon whisk and whip the meringue until glossy and at the soft peak stage. Add the melted gelatine at the very end and mix it in.
Gently fold the meringue and cream into the chestnut mascarpone mixture. Do not over mix.
Transfer the mousse to a one-litre tub and refrigerate until completely set - about six hours.
To prepare the cocoa ganache, measure all the ingredients apart from the gelatine into a small saucepan. Over medium heat, stir and bring to the boil. Boil for two minutes, add the gelatine and transfer to a small container. Leave to cool and set completely - this takes about six hours.
To make the candied chestnuts, cut the fresh roasted peeled chestnuts into quarters. Heat a medium non-stick saucepan with the sugar, butter and chestnuts. Let the sugar start to dissolve and stir continuously to cause crystallisation while the sugar turns to caramel. Boil until a dark caramel colour then pour the candied crystallised chestnuts out on to a lined baking tray. Leave to set and cool. Chop the candied chestnuts into smaller pieces for serving.
For the cocoa filo wafers, preheat the oven to 180°C and line a baking tray with a Silpat.
Melt the butter, sugar and cocoa powder - mix well.
Brush each filo sheet with the melted butter on both sides, place on the tray and place another Silpat on top to weigh it down. Bake for 10 minutes and leave to cool completely.
To serve, crumb the cake crumb into a neat line on a serving plate, place a quenelle of the chestnut mousse off centre on to the cake line, crumb the candied chestnuts and place two smaller quenelles of the ganache on either side. Crack the filo waver into pieces and decorate the plate. Grate over a fresh chestnut and finally place a few pieces of gold leaf on to the plate and serve immediately.