01 - Preheat your oven to 175°C (350°F). Prepare a 23x13 cm (9x5-inch) loaf pan by greasing and flouring it, or lining it with parchment paper.
02 - In a large mixing vessel, whisk together the mashed bananas, eggs, peanut butter, melted butter, brown sugar, and vanilla extract until a smooth emulsion is achieved.
03 - In a separate vessel, combine the flour, baking soda, baking powder, salt, and cinnamon.
04 - Gradually introduce the dry ingredients into the wet mixture, folding until just incorporated. Avoid overmixing.
05 - Gently fold in the chopped peanuts or chocolate chips, if utilizing.
06 - Pour the batter into the prepared loaf pan and level the surface.
07 - Bake for 50–55 minutes, or until a testing probe inserted into the center emerges clean or with a few moist crumbs.
08 - Allow the baked item to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely prior to slicing.