In a small bowl, mix the ground flaxseed and the water. Set aside.
In a large bowl mix the almond flour, sugar, baking powder, salt and cinnamon.
In a separate bowl, combine the mashed banana, coconut oil, and vanilla. Add the ground flaxseed mixture. Mix well and put this mixture in a well greased loaf pan or prepared with a parchment paper.
Bake for 50 minutes or until golden brown and firm to the touch. When you put a toothpick in the center it should come out clean.