In a bowl, mix together the dry ingredients - flour, baking powder and baking soda.
In another bowl, mix the butter and sugar very well.
Add the egg and vanilla extract to the butter sugar mixture and beat well until well combined.
In a separate bowl, mash the ripe bananas very well (I recommend mashing very well so that it will blend nicely with the batter).
Add the mashed bananas to the butter sugar egg mixture and mix everything well.
Add the banana butter mixture to the dry flour mixture and gently mix in to blend everything well. You can use a balloon whisk to mix the ingredients easily.
Finally add the chocolate chips to the muffins batter and gently mix using a spoon to fold in the chips.
If you are using a regular non stick mini muffin pan or silicon mini muffin pan, you don't have to grease the pan, if you are using a steel or aluminium mini muffin pans, make sure to grease the pans with cooking oil before you add the batter.
Once the pan is ready, add the muffin batter to the muffin cups in the pan, you can fill the cups with the batter for about ¾th of the cups (if you add too much batter it may become difficult to handle later). If you are using silicon muffin pan you may need to keep the muffin pan on top of a regular cookie sheet or baking sheet to make it stay sturdy while baking.
Preheat oven to 350 degree Fahrenheit.
Bake for about 16 minutes until the muffins are perfectly baked and very lightly browned on top. Enjoy the mini chocolate chip banana muffins for breakfast or snack as you wish!