Step 1: Preheat your oven to 350°F (175°C).
Step 2: Grease a 9x5-inch loaf pan with butter or non-stick spray.
Step 3: In a large mixing bowl, cream the softened butter and granulated sugar until light and fluffy.
Step 4: Add the eggs one at a time, mixing well after each addition.
Step 5: Stir in the mashed bananas, buttermilk, and vanilla extract until well combined.
Step 6: In a separate bowl, whisk together the flour, baking powder, salt, and baking soda.
Step 7: Gradually add the dry ingredients to the wet ingredients, mixing gently until just combined.
Step 8: Pour the batter into the prepared loaf pan and smooth the top.
Step 9: Bake for 60-70 minutes, or until a toothpick inserted comes out clean.
Step 10: Let it cool in the pan for 10 minutes before transferring to a wire rack to cool completely.
