Gather all ingredients. Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x5-inch loaf pan.

Stir sugar and melted butter together in a large bowl. Add eggs and vanilla; mix well. Combine flour, baking soda, and salt; stir into butter mixture until smooth.

Fold in banana slices, sour cream, and walnuts; transfer into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center of the loaf comes out clean, about 1 hour.

Cool loaf in the pan for 10 minutes before inverting onto a wire rack to cool completely.

Serve and enjoy!