Place 4-5 bananas in the mixer and run on low until bananas are mashed
Add egg, sugar, and oil to mixture. Mix for about two minutes until sugar is dissolved.
Mix in baking soda, baking powder, and flour.
Once completely mixed in add cinnamon and walnuts.
Mix for about 1-2 minutes stopping once to scrape sides of bowl.
Pour dough into a 9 x 5 pan and bake at 350 degrees for about 50 minutes.
Remove from the oven and allow to cool for about 2-3 minutes.
Place the banana bread in a large zip-lock bag in fridge to lock in moisture.
Serve when cooled. Enjoy!