Preheat Oven: Heat your oven to 350°F (175°C). Grease a 9×5-inch loaf pan or line it with parchment paper.
Combine Wet Ingredients: In one bowl, mash the ripe bananas, then stir in melted unsalted butter, brown sugar, vanilla extract, and eggs. If using sour cream or yogurt, fold it in as well.
Mix Dry Ingredients: In another bowl, whisk all-purpose flour, baking soda, and salt until combined.
Combine Wet and Dry: Gently fold the dry mixture into the wet mixture. Stir until just blended; overmixing can cause a dense loaf.
Add Optional Mix-ins: Fold in chopped walnuts or chocolate chips if desired.
Bake: Pour the batter into your prepared loaf pan. Bake for about 50–60 minutes, or until a toothpick inserted in the center comes out clean.
Cool and Serve: Allow the bread to cool in the pan for about 10 minutes before transferring it to a wire rack. Slice and enjoy your moist banana bread.