This Christmas dessert which is delicious at any time of the year is based on the French classic, can be made several weeks ahead. Just take it from the freezer 40 minutes before serving, ready for its final flourish.
Cuts into 9 squares
1. Heat oven to 140oC/fan 120oC/gas. Line the base of a loose-bottom 20cm square tin.
2. Tip 25g of the walnuts into a food processor and blitz until ground as finely as possible; add the rest of the walnuts, then pulse to chop roughly. Tip the egg whites into a clean bowl, whisk until peaks have formed, then gradually add the sugar a third at a time, beating between each addition until stiff.
3. Fold in the walnuts. Tip the meringue into the tin, then spread over the base. Bake for 2 hrs until crisp, then leave to cool. (This can be done 1 day in advance and covered in cling film.)
1. To assemble, leave the ice cream to soften slightly so it's pliable, but not melted. Workings quickly, in one of the bowls, mix half of the ice cream with half a jar of the puree to make chestnut ice cream. If it's too soft once you have mixed it, place the bowl in the freezer to firm up. Once all the ice cream is the same consistency, quickly ripple the vanilla and chestnut ice creams and the remaining puree from the opened jar together. Spread over the meringue and smooth the top, then place in the freezer until frozen solid. This can be done 1 month in advance and frozen, covered in cling film.
2. To serve, remove the cake from the freezer, and then place in the fridge for 40 mins. Whip the cream until stiff. Mix in 200 g puree, continue to beat until it becomes stiff again, then tip the cream into a piping bag fitted with a small round nozzle. Using a large knife dipped into hot water cut the cake into 9 squares. Working quickly, pipe a 'crazy-string' nest of chestnut cream in the centre of each square. Top the cream with a whole sweetened chestnut in syrup and serve straight away.
PER SERVING 641 kcals, protein 9g, carbs 95g. fat 28g. sat fat 14g, fibre 2g, sugar 83g. salt 0.48g
Based on a recipe by Barney Desmazery published in BBC Good Food Magazine DECEMBER 2008