Preheat the oven to 355F (180C) and line a muffin pan with 9 muffin liners.
In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.
In the bowl of a stand mixer fitted with a paddle attachment (or use a hand mixer and a bowl), cream together the white sugar, brown sugar, unsalted butter, and vanilla extract until light and fluffy. Then, add the oil and beat until it has incorporated.
Add the egg, and mix well until emulsified.
Add the puréed bananas and beat to incorporate.
Sift in the flour, salt, baking powder, and baking soda, and mix on low just until fully incorporated and no dry ingredients are left.
Fold in the chocolate chunks and spread the batter between the muffin liners so they’re ⅔ full.
Bake for 23-25 minutes or until a toothpick inserted in the center comes out clean and the tops are golden.
Remove from the oven and let cool down for 5-10 minutes in the pan. Place onto a cooling rack to cool down completely.