Preheat oven to 350º F and lightly grease a 9x5-inch loaf pan with butter or non-stick spray.

Place the bananas in a large bowl and mash them until mostly smooth. Stir in the melted butter.

Mix in the eggs and vanilla extract. Sprinkle the cake mix on top of the banana mixture and mix until incorporated

If you're using pecans or other nuts add them in now and incorporate well. You want the nuts equally distributed throughout the bread.

Pour the batter into the loaf pan, sprinkle with more pecans if using, and then place in the oven and bake for 45-55 minutes, or until a toothpick inserted in center comes out clean.

Place the pan on a cooling rack and allow to cool about 15 minutes. After 15 minutes remove from the pan and allow the loaf to cool on the rack for at least one hour and preferably two to prevent crumbling when slicing. For easier slicing, store loaf tightly covered 24 hours.

Cut with a serrated knife, using a light sawing motion.