Adjust oven rack to middle position. Preheat oven to 325° F. Grease and flour a 9x5 inch loaf pan.
In a medium bowl whisk the flour, baking soda, baking powder, salt, and cinnamon. Set aside.
In stand mixer fitted with a paddle attachment (or using a hand mixer) beat the butter and sugars until well creamed, about 2 minutes on medium speed. Add the eggs, one at a time, beating well after each addition. Add the sour cream, bananas, and vanilla and mix until fully combined about 1 minute.
Add the dry ingredients and mix until just combined.
Pour the batter into the prepared loaf pan. Bake for 70-80 minutes or until a toothpick inserted in the center comes out clean.
Remove from oven and let cool in pan for 10 minutes. After 10 minutes carefully remove the loaf from the pan and let cool completely on a wire rack.
Cover and store banana bread at room temp for 2 days, or in fridge for up to 1 week.
Make sure the oven is heated to 325°F. I use an oven thermometer to make sure the oven is at the right temperature. Make sure you use overly ripe bananas, they provide great flavor. Banana bread tastes amazing come day 2, this gives the flavors time to meld together. Banana bread can be frozen for 2 months. Double wrap in plastic wrap and then cover in aluminum foil.