In a bowl, mix together the dry flour, baking powder, baking soda and sugar until they are evenly combined.
Mash the bananas very well in another bowl.
Add the oil and vanilla extract to the mashed bananas, mix well.
Add the banana mixture to the dry flour mixture, mix very well until there is no more dry flour. The cookie dough should be sticky in texture.
Refrigerate the mixture for about 30 minutes.
Meanwhile preheat the oven at 350 degree Fahrenheit.
After chilling the dough for 30 minutes, add the chocolate chips and mix in evenly with the dough.
Prepare a baking sheet lined with parchment sheet and drop spoonfuls of cookie dough onto the sheet.
The cookies will spread slightly while baking so make sure to leave some space between the cookies if you do not want them to stick together (If necessary, you may bake the entire cookies in two batches if there's no enough space in the cookie sheet).
Bake for 12 to 14 minutes until the top of the banana cookies are lightly browned.
Once the cookies are baked, immediately transfer the cookie sheet from the hot oven and allow the cookies to cool down for few minutes.