Preheat oven to 350º Fahrenheit. Lightly grease a standard-sized loaf pan and set aside.
In a medium-sized bowl, add your flour, baking powder, baking soda, and salt. Whisk until everything is combined. Set aside for now.
In another bowl, cream together the softened butter and brown sugar until the mixture is light and fluffy. Then add in your eggs and whisk until smooth. Lastly, add the mashed bananas and mix until combined.
Add your dry ingredients to your moist ingredients and stir just until combined. Do not overstir. A few lumps are completely fine.
Pour the mixture into the prepared loaf pan. Bake for one hour or until the top is nice and golden brown. Enjoy!