Preheat oven to 350° Fahrenheit.
Mash bananas using a fork or potato masher.
On a separate large mixing bowl, mix in all dry ingredients such as the flours, salt, baking powder, baking soda, and cinnamon.
On another mixing bowl, whisk in all the liquid ingredients such as the sweetener, flax egg, coconut oil, earl grey black tea, and vanilla. Whisk until well combined.
Combine liquid ingredients with dry ingredients. Then add in the mashed bananas. Fold batter together. Do not overmix the batter.
Fold in the walnuts onto the batter until well combined.
Generously grease loaf pan with oil on all sides. Line a parchment paper on the bottom of the loaf pan so that it is easier to remove after baking.
Pour in the batter and even out onto the loaf pan. Sprinkle with raw sugar (optional) and cinnamon before baking into the oven.
Bake in the oven for 45 minutes to 1 hour or simply pierce a toothpick or fork to see if it is dry (or clear). Allow the loaf to cool on a cooling rack for at least 30 minutes to an hour.