1: 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: Beat until evenly mixed.
3: 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: Chop 40 g marrons glacés (candied chestnuts) into small dice.
5: 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: Put a little of the mixture into each cake mould or tin, then add a few chopped marrons glacés on top.
7: Cover with more cake mixture (you should not be able to see the marrons glacés), then glaze the tops.
8: 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.