Prep your pan and oven. Heat the oven to 350°F (175°C).
Grease a 9x5-inch loaf pan and line it with a parchment sling for easy removal.
Mash the bananas. In a large bowl, mash bananas with a fork until mostly smooth with a few small lumps. You should have about 1 1/4 cups.
Whisk in wet ingredients. Add melted butter, oil, brown sugar, eggs, and vanilla. Whisk until the mixture looks cohesive and glossy.
Combine dry ingredients. In a separate bowl, whisk flour, baking soda, baking powder, salt, and cinnamon.
This keeps leaveners evenly distributed.
Bring it together. Add the dry ingredients to the wet and fold gently with a spatula until a few streaks of flour remain. Do not overmix.
Add the chocolate chips. Fold in mini chocolate chips (and nuts, if using). The batter will be thick and scoopable.
Fill the pan. Scrape the batter into the prepared loaf pan.
Smooth the top and sprinkle the extra chips over the surface for a bakery-style look.
Bake. Bake for 55–65 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs, not wet batter. If the top browns too quickly, tent loosely with foil at the 45-minute mark.
Cool. Let the loaf rest in the pan for 10–15 minutes, then lift it out and cool on a wire rack. Wait until it’s barely warm before slicing for the neatest slices.
Serve. Enjoy plain, with a swipe of butter, or slightly warmed.
The flavor deepens by day two.