Preheat the oven to 350°F with a rack in the center position.
Grease a standard 9x5-inch loaf pan with cooking spray or a light brush of vegetable oil, then dust lightly with flour and tap out the excess. Alternatively, line with parchment paper, leaving an overhang on the long sides — this makes it easy to lift the loaf out completely clean.
Mash the Bananas
Peel the overripe bananas into a large bowl and mash thoroughly with a fork until no large chunks remain — the texture should be almost smooth with a few small pieces. The bananas should be deeply fragrant and almost liquid at this stage. If they're still holding their shape easily, they're not ripe enough.
Mix the Wet Ingredients
Add the vegetable oil, sugar, eggs, and vanilla extract to the mashed bananas.
Whisk together until fully combined and the sugar has dissolved into the mixture. The batter will look loose and slightly curdled at this stage — that's normal.
Combine Dry Ingredients Separately
In a separate bowl, whisk together the flour, baking soda, and salt until evenly combined.
Mixing the dry ingredients together first ensures the baking soda and salt distribute evenly through the flour before they touch the wet ingredients.
Fold Wet and Dry Together - Carefully
Add the dry ingredients to the wet ingredients all at once. Fold together with a rubber spatula using broad, gentle strokes — scraping the bottom of the bowl and folding over the top.
Mix until just combined. Stop when you can no longer see large pockets of dry flour. A few small streaks are fine.
This is the most important step — overmixing from here produces a dense, tough loaf.
Add the Chocolate Chips
Toss the chocolate chips in 1 tablespoon of flour to coat them lightly — this helps them stay distributed through the batter rather than sinking to the bottom.
Fold them into the batter with 3 or 4 gentle strokes. No more mixing than necessary.
Bake
Pour the batter into the prepared loaf pan and gently smooth the top gently.
Place in the center of the preheated oven. Bake for 55 to 65 minutes. Start checking at 55 minutes by inserting a toothpick into the center of the loaf — it should come out clean or with a few moist crumbs attached. If the top is browning too fast before the center is done, tent loosely with foil and continue baking.
Do not go by the color of the top. Banana bread browns quickly because of the sugar content — a dark brown top does not mean a done loaf.
Rest Before Slicing
Remove from the oven and let the loaf rest in the pan for 10 minutes — the loaf is still setting as it cools, and cutting too early collapses the crumb.
After 10 minutes, transfer to a wire rack and wait another 10 minutes before slicing. The wait is worth it.