Preheat oven to 350 degrees F. Line a 8×4 loaf pan with parchment paper 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 a medium bowl, add the flour, ground flaxseed, baking soda, cinnamon, salt, and sesame seeds. Whisk to combine well.
In the bowl with the flax egg, add the bananas mash well. Add the maple syrup, milk, tahini, and vanilla. Whisk until well combined and smooth.
Add the dry ingredients to the the wet. Mix with a spatula until just combined. Do not over mix!!! Pour batter into the loaf pan and slice the extra banana in half lengthwise and place on top (optional). Sprinkle with extra sesame seeds. Bake for 55-65 minutes or until toothpick or knife comes out clean. Let it cool in the pan for 10 minutes then carefully remove the bread and place on a wire rack to cool completely. Enjoy! Place leftovers in an airtight container or a ziplock bag. It tastes even more flavorful and moist the next day!