Add the buttermilk to a large bowl. If you're using the vinegar plus milk option, let sit for about 10 minutes to allow the milk to turn to buttermilk.
Add mashed banana, eggs, butter, and vanilla into the buttermilk and whisk together.
In another bowl, whisk together the flour, sugar, baking powder, baking soda, chocolate chips and salt to combine.
Pour the dry ingredients into the wet ingredients and mix just just until incorporated. Do not overmix!
Let the batter rest for about 5-10 minutes. It should form bubbles and rise up a bit.
Heat a griddle to 325 degrees or place a large griddle or frying pan over medium heat. Melt a little butter on the cooking surface, spreading it evenly. Using a 1/3 cup measure (or a large cookie or ice cream scoop), pour the batter onto the griddle or into the frying pan. The pancakes are ready to flip when they look a little dry around the edges and start to form little bubbles approximately a minute or so. Flip and cook on the other side until golden brown and the cooked through.
Serve topped with sliced bananas, butter and maple syrup. Additionals: Pecans, walnuts, whipped cream, more chocolate chips