1. Preheat the oven to 180°C (fan: 160°C).
2. Grease a loaf pan (approx. 23 × 10 cm).
3. Mash the bananas in a bowl with a fork.
4. Add the oil and brown sugar and mix well.
5. Mix in the eggs one at a time.
6. In a second bowl, combine flour, baking powder, salt, and cinnamon.
7. Scrape the seeds from the vanilla bean and add them.
8. Add the dry ingredients to the banana mixture and stir just until combined.
9. Pour the batter into the prepared pan and smooth the top.
10. Bake for about 60 minutes, then check the cake with a knife.
11. Let the bread rest for 10 minutes, then cool down on a rack or plate.