For the chestnut flan, cut the chestnuts crosswise. Pre-cook in hot water for 10 minutes and peel.
Boil chestnuts with honey and half of the whipping cream for 10 minutes with the lid closed until soft. Remove from heat, make chestnuts into puree and pass through a fine sieve. Fold in almond liqueur.
Bring milk with slit vanilla bean to a boil and allow to infuse for a bit. Then remove the vanilla pod.
Stir the sugar with the egg yolks until creamy, pour in the hot milk and heat, stirring, until just boiling point. Remove from heat.
Soak gelatin in cold water for 5 minutes. Remove and melt in the hot egg milk. Pour into a bowl and let cool.
As soon as the cream begins to gel, fold in the pureed chestnuts. Whip remaining whipped cream until stiff and fold in. Pour into cold rinsed custard cups and chill.
Turn Maroniflan out onto dessert plates and serve.