Preheat oven to 170 degree C (340F). Lightly grease a loaf pan with butter and line with a parchment paper (butter paper). Keep aside.
Peel the ripe bananas and take them in a bowl. Mash them using a fork and set aside.
In a large bowl, sift flour, baking powder, and baking soda together and keep it ready.
In a separate bowl, combine oil, butter, and sugar to make a paste like consistency. It takes few minutes time and vigorous whisking using mechanical or electrical blender to achieve this consistency.
Next add each egg at a time and whisk the batter well.
Add cinnamon powder and mix well.
Now mashed banana into the wet ingredients and mix well.
After that, fold mixture of dry ingredient into wet ingredients.
Then fold in ⅔ of the chocolate chips and pour the batter into the lined pan.
Spread the batter even and add the remaining chocolate chips on the top of it.
Bake it in the preheated over for 45 minutes to 1 hour or until toothpick comes out clean.
Allow the cake to cool completely and later remove the cake from the pan.
You can slice the loaf and store them in a dry air-tight container.