Mash the bananas.
In a bowl, combine the mashed bananas, sugar, eggs, and melted butter and mix well.
Sift in cake flour, baking powder, and salt, then mix together.
Chop walnuts and add them to the batter to finish.
Pour the batter into a pound cake mold lined with parchment paper.
Bake in a preheated oven at 180°C for 40–45 minutes.