Prepare the Oven and Pan: Begin by heating the oven to 350°F. Grease a standard loaf pan and lightly dust it with flour so the bread releases easily later. This step helps the loaf bake evenly and keeps the sides from sticking once it cools. Set the pan aside while you mix the batter.
Mix the Dry Ingredients: In a medium bowl, stir together the flour, baking soda, salt, and cinnamon. Use a whisk to break up any clumps and evenly spread the leavening. This step makes sure the bread rises evenly and avoids pockets of baking soda in the finished loaf.
Combine the Wet Ingredients: In a large bowl, whisk the melted butter with both sugars until smooth. Add the eggs one at a time and mix well after each addition. Stir in the mashed bananas, sour cream, and vanilla until the mixture looks creamy and well blended. The batter should smell sweet and slightly tangy at this stage.
Bring the Batter Together: Add the dry ingredients into the wet mixture in small portions. Gently stir just until everything comes together. Stop mixing as soon as you no longer see dry flour. Overmixing can make the loaf dense, so keep the motion slow and light. Fold in any add ins at this point.
Bake the Banana Bread: Pour the batter into the prepared pan and smooth the top. Place the pan in the oven and bake for 55 to 65 minutes. The bread is ready when a toothpick inserted into the center comes out mostly clean with a few moist crumbs. Let the loaf cool in the pan for ten minutes before removing it.
