Preheat the oven to 350°F. Line a loaf pan with parchment paper or greased foil. Set aside.
Peel bananas and add to a large mixing bowl. Using a dough blender (recommended) or sturdy whisk/fork, mash bananas until smooth. Add the coconut oil, maple syrup, flax egg and vanilla. Whisk until well incorporated.
In a medium bowl, sift together: oat flour, cacao powder, almond meal, baking powder, baking soda and salt.
Add dry ingredients to wet ingredients. Whisk together until just incorporated, making sure no flour patches remain. Fold in chocolate chips.
Pour batter evenly into prepared loaf pan. Using a rubber spatula, smooth batter into an even layer, with a rise down the center. Batter is a little liquidy, but can be shaped a bit—using a rubber spatula, cut batter away from the sides and gather at the center for a bit more of a rise. Optionally, sprinkle with chocolate chips and lightly press down into loaf.
Bake for 60-70 minutes. Mine took 65 minutes. Test for doneness by sticking a toothpick into the center of the loaf. The toothpick will come out clean when the loaf is done.
Cool in pan placed on a cooling rack for 1 hour. Pinch parchment paper & lift paper + banana bread onto cooling rack to complete cooling, about 1-2 additional hours. Slice and enjoy.
A Note on Homemade Oat Flour: *If using homemade oat flour, make sure to blend the flour until very fine and sift the flour to remove coarse bits of oats that could create less than ideal results. Store until needed, then measure the amount required for the recipe.Storing Notes: Store in an airtight container for up to 1 week.Freezing Instructions: This loaf freezes well. Wrap in parchment paper and store in an airtight container in the freezer for 1-2 months. Allow to thaw at room temperature for 30 minutes, or pop in the microwave in 10-second increments until just warm.