Adapted from Nigella Lawson's Nigellissima, as I loved her ingenious Italian addition of coffee powder to banana bread. However, I've reduced the sugar by well over half the original recipe's quantity, adding chestnut flour to add that rustic Corsican touch! If you can't find chestnut flour, use buckwheat for a delicious alternative.
Preheat the oven to 170°C/150°C fan/340°F (gas mark 3). Lightly oil a 450g/1LB loaf tin or no need to oil if using a silicone loaf mould.
Mash the bananas to a purée, add the salt and beat in the oil. Beat in the eggs, one by one, followed by the soft brown sugar.
Sift the chestnut flour and gradually beat it into the mixture, adding the plain flour, bicarbonate of soda, coffee powder and walnuts (if using).
Pour the batter into the loaf tin, place on a baking sheet and bake in the oven for 50-60 minutes, or until slightly coming away at the sides and bunglingly risen. A cake tester should come out clean.
Leave the cake in the tin for about 20 minutes, then turn out on to a wire tray to cool.
For a gluten-free banana bread, then omit the plain flour and use 170g chestnut flour. To make muffins, pour the mixture into a greased 1x12 muffin tin (or silicone brochette moulds, so no greasing necessary) and bake for 20 minutes at 200°C (gas mark 6).Leave the cake or muffins overnight as they'll taste even better in the morning. Store in an airtight container for up to 5 days. The muffins/cake also freeze well for up to 3 months; just defrost the night before.