For the banana cornflake cake, peel the bananas and mash them with a fork. Crush cornflakes with the help of a mortar and mix with banana mash.
Preheat the oven to 180 °C. Grease a loaf pan. Mix flour with nuts and baking powder.
Cream butter, sugar and vanilla in a food processor and add eggs one at a time, beating until fluffy. Add flour mixture and banana-cornflakes mixture and stir in both briefly.
Pour mixture into loaf pan and bake banana cornflakes cake for 45 minutes.