Preheat the oven to 180°C. Crush 10 Gavottes. Place the flour, chopped almonds, cubed butter, brown sugar and 10 crushed Gavottes in a bowl. Make a crumble. Place the crumble on a baking tray lined with parchment. Bake for 10 to 15 mins. Remove the crumble from the oven and set aside.

Pour 5 cl water into a pan, add the chocolate squares and melt over a low heat. Off the heat, add the chestnut cream and mix with a spatula. Allow to cool. Add the remaining crushed Gavottes. Whip the cream into a chantilly. Combine with the previous mixture. Pour the mousse into verrines and refrigerate. To serve, sprinkle the crumble over the verrines.