Preheat oven to 350 degrees. Line a 9×5 loaf pan with parchment paper.
In a large mixing bowl, make flax eggs by combining the ground flax seeds with water. Let it sit for 5 minutes to thicken. Add the bananas and mash very well until smooth. Add the vanilla, melted coconut oil, coconut sugar, and apple cider vinegar. Whisk together until well combined.
In a separate bowl, whisk together the oat flour, almond flour, baking soda, baking powder, cinnamon, and salt.
Add dry ingredients to wet. Use a spatula and mix until just barely combined and there are no more lumps. Careful not to overmix. Fold in the chocolate chips.
Pour into the lined 9×5 loaf pan. Top with extra chocolate chips. Bake for 55-65 minutes. Mine took about 60 minutes. It is done when a toothpick inserted in the middle comes out clean. Let the bread cool in the pan for 5 minutes, then lift the bread out with the parchment paper and place on a cooling rack. Cool completely before cutting.
Enjoy! Store in an airtight container or ziploc bag on the counter for 3 days or in the fridge for 5 days.