Add flour, baking powder, baking soda and salt to a medium size mixing bowl and whisk together. Set bowl aside.
Add eggs, granulated sugar, brown sugar, and vegetable oil to a separate, large mixing bowl. Use a spoon to stir until smooth.
To the sugar and oil mixture, add mashed bananas, sour cream, and vanilla extract. Stir until well combined.
Add half the dry ingredients to the wet ingredients and stir gently, just until the dry ingredients are mostly incorporated. Add the remaining dry ingredients and continue stirring gently. Stop as soon as the dry ingredients are just incorporated and no dry patches of flour remain. Try not to overmix because it can create tough banana bread.
Gently fold chopped walnuts into batter.
Lightly spray a large (12 cup) bundt pan with non-stick cooking spray. Pour batter into bundt pan and spread it evenly around the pan.
Bake on the middle rack of your preheated oven for 45-55 minutes. Remove as soon as a knife inserted in the middle comes out clean.
Let banana bread cool in the pan for at least 20 minutes before removing. To remove, place a large plate on top of the bundt pan then flip the bundt pan over so that the bread slides out onto the plate. Cut and serve once it has cooled completely. Enjoy!
Notes
Note – Calorie counts are only an estimate and will vary based on the ingredients you use