Preheat the oven to 350 degrees F. Grease a 9x5-inch loaf pan with nonstick cooking spray and set aside.
In the bowl of a stand mixer or by using a hand mixer, cream butter and sugar together. Add eggs, mashed bananas, buttermilk, and vanilla until combined.
Add in the flour, baking powder, salt and soda. Mix until just combined. Pour batter into prepared pan and bake for 50-55 minutes or until a toothpick comes out clean.
Let bread cool on a wire rack for 15 minutes. Loosen the bread with a knife and carefully remove from pan. Let the bread cool completely on the cooling rack. Slice and enjoy!
Notes
Store on the counter for up to 3 days or freeze for up to 3 months.