Preheat your oven to 325 degrees. Spray an 8x5 or 9x5 loaf/bundt pan with nonstick baking spray. If using a 9x5 pan you will need to reduce the baking time slightly.
Add your butter and sugar to a bowl and mix on high for 3 minutes until light and fluffy.
Add in your banana, eggs, and vanilla and mix to combine.
Add in all of your dry ingredients and mix until everything is just incorporated. Don't over mix.
Pour batter into your prepared loaf pan. Bake for 55-65 minutes or until a toothpick comes out clean and the top is golden brown.
Allow to cool for 20 minutes before flipping out from the loaf pan onto a cooling rack. Allow to cool completely.