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 flaxseeds 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 over mix!
Pour 1/2 of the batter into the lined 9×5 loaf pan. Sprinkle half of the cinnamon mixture on top. Then pour the last half of the batter on top of the cinnamon layer. Sprinkle evenly the last half of the cinnamon mixture on the top. With a knife, lightly swirl the cinnamon into the batter. Don’t go crazy with this because you want to see the layers. Bake for 60-70 minutes. Mine took about 65 minutes. It is done when a toothpick or knife 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.