Step by step recipe:

1. 3 min.
   Put into a mixer bowl: 30 g ground almonds, 30 g ground hazelnuts, 30 g cornflour and 50 g butter, cut into small pieces.
2. 4 min.
   Beat until evenly mixed.
3. 30 min.
   Add 100 g egg, 300 g sweet chestnut purée (crème de marrons), 1 tablespoon rum and 1 pinch fine (or table) salt.
   
   Continue beating until evenly mixed.
   
   Refrigerate for at least 30 minutes.
4. 4 min.
   Chop 40 g marrons glacés (candied chestnuts) into small dice.
5. 4 min.
   Preheat the oven to 390°F (200°C).
   
   You can put the mixture into a forcing bag to make life easier, but this is not essential.
6. 4 min.
   Put a little of the mixture into each cake mould or tin, then add a few chopped marrons glacés on top.
7. 4 min.
   Cover with more cake mixture (you should not be able to see the marrons glacés), then use a brush to glaze the tops with beaten egg.
8. 20 min.
   Bake for about 20-25 minutes, watching carefully for browning towards the end of the cooking time. Be careful not to overcook, or the cakes will be too dry.
9. 
   Leave to cool on a wire rack.