Preheat your oven to 350 degrees F. Grease a 9x3" loaf pan with olive oil or your favorite safe baking spray.
In a small heat safe bowl, combine ground flax seed and hot water. Stir to combine, and let sit for 5 minutes for mixture to gel.
In a medium mixing bowl, mash bananas until few lumps remain. Add flax seed mixture, olive oil, and granulated sugar. With a hand mixer or whisk, mix to thoroughly combine.
In a separate bowl, whisk together flour, baking powder, baking soda, salt, and ground cinnamon.
Add dry ingredients into wet ingredients, stirring with a spatula just until a few spots of flour remain. Add chocolate chips if using, and mix until distributed throughout the dough. Do not overmix, a few lumps of flour are fine. The dough will be fairly thick.
Pour dough into greased loaf pan and spread until evenly distributed and top is somewhat flat. Place into preheated oven. Bake for 50 minutes-1 hour, or until toothpick inserted into the loaf comes out clean (melted chocolate is fine!). Cool on a wire rack in the pan for 10 minutes, then turn the loaf out of the pan and cool completely. Slice and enjoy!