Preheat your oven to 190C. Line a muffin tin with paper liners, set aside.
Sift all your dry ingredients (flour, leaveners, sugar) into a large bowl, add the butter and mix it on medium speed till the mixture resembles sand.
Add all your wet ingredients (buttermilk, bananas, vanilla, vinegar) blend them to a smooth mixture.
Once the liquid is ready, pour half of it to the dry mixture and let the mixture run for 1 minute on medium speed. Once that is done, pour the remaining liquid in two parts, mixing after each addition.
Add the chocolate chips and gently fold them in.
Scoop the batter into the muffin tin filling 3/4th way up. Bake for approximately 16-18 minutes or until the top of the muffin springs back up slightly when gently pressed.