2) Pour into a mixing bowl of a paddle mixer with the chestnut puree and mix until the mixture cools down. Fold the whipped cream into the chestnut whisky mixture with a spatula, forming a mousse. Reserve in a plastic pastry bag.
For the chocolate and walnut biscuit:
1) Preheat the oven to 180C/Gas 4.
2) In a bowl mix the egg yolks and 350g sugar. With a spatula fold in the cocoa and chopped walnuts and mix well.
3) In a separate bowl whip the egg whites with the sugar until firm but not stiff. Fold the egg whites into the yolk/sugar mixture.
4) Pour onto a sheet pan on greaseproof paper or a silicone baking sheet and bake for 20 to 30 minutes.
For the whisky syrup:
1) Bring the water and sugar to a boil. Remove from the heat and add the whisky (no heat). Set aside.
For the spiced chocolate sorbet:
1) Bring the water and the sugar to a boil in a large, stainless steel pan. Add the cocoa powder and whisk until smooth. Add the chopped chocolate, honey, bourbon, pepper and espelette.
2) Turn into a sorbet or ice cream maker and freeze following the machine instructions.
For the chocolate glaze:
1) Soak the gelatine sheets in ice water.
2) Bring the 250ml water and the sugar to a boil. Slowly wisk in the cocoa powder, and then the cream. Bring to the boil. Strain the mixture of any lumps and cool down to 62C.
3) Remove the gelatine sheets from the ice water, squeeze dry, and then mix into chocolate. Cool down completely.
To assemble the dessert:
1) Cut 12 each of 3cm and 6cm discs from the chocolate and walnut biscuit. Brush the discs heavily with the whisky syrup. Set aside.
2) Fill each of 12 silicone dome moulds 1/4 way up with the mousse. Put a 3cm disc into each mould, pressing it into the mousse until level with the top.
3) Continue filling the moulds with mousse to within 1cm from the top of the mould. Press a 6cm disc into each mould until level with the top of the mould. Freeze for 4 to 5 hours or until completely frozen.
4) Fully melt the chocolate glaze in a pourable container. Cool down until the chocolate is at room temperature or cool to the touch. Place the completely frozen chocolate mousses on a wire rack. Slowly pour chocolate over each bomb till thoroughly coated. Put onto a sheet tray and refrigerate for an hour.
5) To plate the dessert, brush some melted chocolate glaze onto a circular plate going from ten o' clock to two o'clock. Take one finished chocolate mousse and cut a wedge out of it. Place the chocolate mousse at ten o'clock on the plate and the wedge opposite it at two o'clock. Take a quenelle of chocolate sorbet and place it at four o'clock on the plate.