Preheat your oven to 340°F.
Add the flour, salt, and baking soda to a medium mixing bowl. Set aside.
4 cups all-purpose flour (480 g), 2 tsp baking soda, ½ tsp salt
Mash the bananas in a glass measuring cup or small bowl. Set aside.
4 medium bananas
In the bowl of your stand mixer, cream together the softened butter and white granulated sugar on low speed (3-4 minutes).
1 cup salted butter, 2 cups white granulated sugar
Add the eggs one at a time while mixing on low.
4 eggs
Add the vanilla extract and sour cream. Mix until well incorporated. Scrape down your bowl.
2 cups sour cream, plus 1 heaping tablespoon, 2 tsp vanilla extract
Add the mashed bananas and mix well. Again, make sure to pause and scrape down the bowl.
Add the dry ingredients about ½-1 cup at a time while mixing on low. Mix until just incorporated. Do not overmix! Then, take the bowl off the mixer and scrape it down well with a spoon or spatula to make sure there are no pockets of flour remaining.
Spray 6 mini loaf pans with baking spray (not cooking spray!). Place on a half sheet pan.
Spoon or pour equal amounts of the batter into each of the loaf pans.
Optional—but I highly suggest it! Sprinkle a small amount of white granulated sugar over the top of each loaf for a delicious crust.
Bake the loaves at 340°F for 42-45 minutes, turning the pan 180° at the 20- to 21-minute mark. Check for doneness by sticking a toothpick in the center of each loaf. It should come out clean or with a few moist crumbs stuck to it. Do not overbake!
Allow the loaves to cool for about 5-10 minutes before carefully turning them upside down to remove each loaf from the pan. Use oven mitts or hot pads so as to not burn yourself. Place the loaves on a wire cooling rack to finish cooling.
Slice the banana bread and serve! Wrap leftover loaves tightly with plastic wrap and store on the counter for 3-4 days. This bread will easily stay moist for a few days after baking.