Spray the inside of the bread pan fitted with the kneading paddle with nonstick cooking spray - make sure to spray up the sides of the bread pan.
nonstick cooking spray
Add all of the ingredients into the bread pan in order, making sure the liquid is on the bottom, then secure the pan into your bread maker.
½ cup buttermilk, ½ cup unsalted butter, 2 large eggs, 1 teaspoon pure vanilla extract, 1 ¼ cups ripe bananas, ¾ teaspoon kosher salt, 1 cup granulated sugar, 2 cups all-purpose flour, 1 teaspoon baking soda, ¾ teaspoon baking powder
Next, press the PROG button on your bread maker and select the Cake option. Press the START/STOP button and begin the bread making process.
The bread machine will mix for a bit, so while it is mixing, you can assist it with a rubber spatula and scrape down the sides to make sure that the dry ingredients get fully incorporated into the liquid ingredients. Just be careful that your spatula doesn't get tangled up in the kneading blades. For best results, if you're adding nuts, add them at the end of the mixing cycle so they don't get crushed.
⅔ cup walnuts
At the end of the mixing cycle, let the bread machine begin the baking process and do its thing. It's so easy - just let the bread bake, and the machine does all the work. (And in the summer, this is great because the house won't get hot!)
When the baking cycle is complete, use oven mitts to remove the bread pan from the machine and transfer it to a wire rack to cool completely before slicing