Pour the milk into a glass and add the lemon juice. Let it sit for 5 minutes to make a "buttermilk" You can skip this step if you have buttermilk on hand. Whisk together the flour, brown sugar, baking powder, cinnamon, baking soda, and salt in a bowl.
In a separate bowl, whisk the buttermilk, and vanilla. Add in the mashed bananas and mix again. Next, pour in the dry ingredients and fold with a spatula until just incorporated. Stir in the melted butter and chocolate chips.
Pour ⅓ c waffle batter in a heated waffle iron until golden and crisp, approximately 5 minutes. Serve warm with butter and maple syrup. If your making a lot of waffles preheat your oven ahead on time on a low temperature and place the finished waffles on a baking sheet to keep warm.
