Preheat the oven to 140 ºC hot air for the chestnut biscuits.
Beat the egg whites with 1 pinch of salt and gradually add the powdered sugar until stiff. Stir in half of the chestnut rice. Pour the mixture into a piping bag and pipe into a baking tray lined with baking paper.
Bake for about 20 minutes and let cool.
In the meantime, mix the remaining chestnut rice, honey and rum to make the chestnut filling.
Spread the chestnut filling on two of the biscuits and glue them together.