Step 1: Preheat the Oven

1. Preheat your oven to 350°F (175°C).
2. Grease a 9×5-inch loaf pan or line it with parchment paper for easy removal.

Step 2: Mash the Bananas

1. In a large mixing bowl, mash the ripe bananas using a fork or potato masher until smooth with small lumps remaining. The bananas should be soft and easy to mash.

Step 3: Combine Wet Ingredients

1. Add the melted butter to the mashed bananas and stir to combine.
2. Mix in the egg and vanilla extract, stirring until the mixture is smooth.

Step 4: Add Dry Ingredients

1. In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.
2. Gradually fold the dry ingredients into the banana mixture, stirring until just combined. Be careful not to overmix, as this can make the bread tough.

Step 5: Add Optional Ingredients

1. If using, fold in the sour cream for an extra moist and rich loaf. This step is optional but highly recommended if you want an even softer texture.
2. If desired, stir in chopped walnuts or chocolate chips for added flavor and texture.

Step 6: Pour the Batter

1. Pour the batter into the prepared loaf pan and smooth the top with a spatula.
2. If you’d like, sprinkle a few extra chocolate chips or walnuts on top for decoration.

Step 7: Bake the Banana Bread

1. Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs.
2. If the top of the bread is browning too quickly, cover it loosely with aluminum foil during the last 10-15 minutes of baking.

Step 8: Cool and Serve

1. Once the banana bread is done, remove it from the oven and let it cool in the pan for 10 minutes.
2. Carefully transfer the bread to a wire rack to cool completely before slicing.