Preheat the oven to 350 degrees Fahrenheit. Line an 8 1/2 x 4 1/2 inch loaf pan with parchment paper and set aside.
Puree your ripe bananas in a blender. I find the texture of the bread is much better with pureed bananas (less gummy!) but you can mash them really well if you don't have a blender.
Measure out 1 1/4 cup worth and add to a large mixing bowl. Add in the remaining wet ingredients and whisk really well. To measure the peanut butter, I suggest spraying your 1/2 cup measuring cup with oil so the peanut butter slides right out.
Add in the dry ingredients (aside from the chocolate) making sure to spoon and level the flour to measure. Fold in the chocolate if using. It will be fairly thick.
Transfer to the prepared loaf pan and spread the top out smoothly. Top with extra chocolate chips and a sprinkle of sugar if desired.
Bake for 60-65 minutes or until a toothpick comes out clean. Let cool in the pan for about 15 minutes, then lift out by the parchment paper and let cool on a wire rack. Ideally let it fully cool for 1-2 hours before slicing so it doesn't crumble, the bread really needs time to set! Enjoy as is or with butter and enjoy!