Preheat oven to 375 degrees F. Line a muffin pan or grease well.
In a large bowl, make the flax egg by combining the ground flaxseed with water. Stir and set aside for 5 minutes to thicken.
In another large bowl, add the oat flour, almond flour, baking powder, baking soda, cacao powder, and sea salt. Whisk until well combined.
In the bowl with the flax egg, add the ripe bananas and mash well. Add the maple syrup, coconut sugar, vanilla, melted coconut oil, and almond milk. Whisk until well combined.
Add the dry to the wet. Stir with a spatula until just combined. Careful not to overmix! Fold in chocolate chips. Scoop batter into prepared pan, filling each muffin tin all the way to the top. Sprinkle extra chocolate chips on top if desired.
Bake for 25-30 minutes or until toothpick inserted comes out clean. Let it cool in the pan for 5 minutes, then transfer muffins to a wire rack to cool completely. Enjoy! Store in an airtight container on the counter for 3 days.