Preheat the oven to 350 degrees F. Butter and flour a 9 by 5 by 3-inch loaf pan.

In a large bowl, whisk together the flour, baking soda, baking powder and salt.

In a separate small bowl, mash the bananas with a wooden spoon, leaving a bit of texture.

In another large bowl, use a hand electric mixer or stand mixer to cream the 1/2 cup of butter and sugar together until light and fluffy. Add the eggs, 1 at a time.

Stir in the mashed bananas, sour cream and vanilla and beat until just combined.

Add the dry ingredients and gently stir in pecans. Pour the batter into the pan and put on a sheet tray.

Bake for 1 hour. Let cool for 5 minutes in the pan then turn out onto a wire rack to finish cooling.