Whisk the flaxseed meal and water together in a small prep bowl and allow it to thicken for a few minutes. Line your muffin pan with parchment paper or cooking spray.
Mash the ripe bananas in a medium bowl, getting rid of most of the clumps. Add the flaxseed mixture and stir to combine.
Add the baking soda, coconut sugar, maple syrup, tahini, salt, vanilla, and avocado oil. Whisk to combine. Add the sifted cocoa powder and whisk again.
Add the rolled oats and almond flour and stir to combine. The mixture should be scoopable and not too runny. If it's too wet, add more almond flour a little bit at a time.
Divide the batter evenly amonst the muffin tins. Top each muffin with a few extra chocolate chips.
Using the 'Convection Bake' setting on your oven, bake at 325°F for 25-30 minutes. If you do not have this setting, bake at 350°F for 25-30 minutes. Muffins will be done when a toothpick inserted into the centre comes out mostly clean.
Pan rest for 10 minutes before transferring to a wire cooking rack. Cool completely before serving for the best texture.