Preheat the oven to 160 °C or 140 °C fan bake. Spray a loaf pan with oil spray.
Dry mixture
Mash 4 bananas in a large bowl with a fork until smooth. Add 2 egg, ½ cup olive oil, ¼ cup milk and 1 tsp vanilla extract and stir until combined.
Dry mixture
Sift in 1 cup wholemeal flour, 1 cup flour, 1 tsp cinnamon, 1 tsp baking powder, 1 tsp baking soda and a pinch of salt. Stir until combined.
Bake bread
Spoon into prepared pan and level top with a spatula. Bake for 1 hour 10 minutes or until a skewer inserted in the centre comes out clean. Stand in pan for 5 minutes before transferring to a wire rack to cool.