In a blender, combine the melted butter, eggs, bananas, sour cream, vanilla extract, and sugar in the specified order. Pulse the mixture until it’s just blended, about 4 pulses.
Add all the dry ingredients to the blender. Pulse a few more times, about 4-5, until everything is combined. Be careful not to overblend, as it can lead to a dry and dense banana bread.
Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius). Grease a 9×5 loaf pan or line it with parchment paper.
Pour the batter into the prepared loaf pan.
Bake for 45 minutes initially. Then, loosely cover the bread with foil and bake for an additional 15 minutes or until a toothpick inserted into the center comes out clean.
Let the banana bread cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.
Enjoy your freshly baked blender banana bread!