Line the muffin pan with liners and keep it aside. Preheat the oven to 180℃/350°F.
In a small bowl mix milk and vinegar. Set aside.
In a large mixing bowl add the peeled bananas & mash using a fork till you get a gooey mashed consistency. You can also use your mixer to mash the bananas
Stir in the milk-vinegar mix, melted butter, and vanilla extract. Whisk until well combined.
Sift all the dry ingredients like flour, baking powder & baking soda, and salt in another bowl. Also, add sugar and mix till combined. Add the chocolate chunks and chips.
Mix dry ingredients and wet ingredients. Mix until just combined.
Pour the batter with the help of a scooper or spoon into the muffin pan.Fill up to the brim. Add some chocolate chunks/chips on top.
Bake in the preheated oven for 25-30 minutes or until a golden brown colour is achieved by muffins. A skewer or toothpick inserted in the centre of the muffin should come out clean.
Let it rest in the pan for 8-10 minutes then place on a wire rack to cool completely.