Preheat the oven to 350 degrees Fahrenheit.
Peel and mash the bananas and make sure you have a full 1 3/4 cup worth. If you have less, add in another half of a banana until you get the full amount.
I have also tested this recipe with pureed banana instead of mashed, and really like the result. It yields a slightly more fluffy muffin without any dense pockets from banana, but you can do either.
To the same mixing bowl, add the egg , apple cider vinegar, vanilla, sugar, oil and whisk together.
Next, whisk in the oat flour, almond flour, baking soda, baking powder, cinnamon and salt.
Mix well until a batter forms.
Fold in the chocolate chips.
Scoop out the batter and add to a lined muffin tray, filling each spot about 3/4 of the way up. I like to use a cookie scoop to ensure evenly sized muffins. Bake for 18-22 minutes or until a toothpick comes out clean or with just a few crumbs. Let cool, then enjoy!