Mix the dry ingredients together: In a medium bowl, sift together the flour, baking soda, baking powder, salt, and the remaining ½ teaspoon of the cinnamon, whisking well to combine once sifted into the bowl.
Make sure your flax eggs are ready - they will have a thickly gelled or goopy texture. If any extra water is sitting on top of the mix, just mix thoroughly again before using so that you have a thick and viscous mixture.
Mix the wet ingredients together: In a large bowl, add the wet ingredients together, adding the maple syrup, oil, oat milk, mashed banana, flax eggs, and vanilla extract, thoroughly whisking until combined.
Add the dry ingredients into the wet ingredients and using a silicone spatula or wooden spoon, gently mix until just combined - as you’ll mix again in a moment, it’s ok if a few spots of flour still show, so don’t overmix.
Sprinkle in the chocolate chips, and briefly mix again until just combined.
Scrape out the batter into the prepared pan and make sure it is evenly distributed.
Sprinkle the cinnamon sugar mixture on top of the loaf, and it let it sit for a minute or two so that the sugar can soak up some moisture.
Place the pan into the centre rack of the oven and bake for 55 - 65 minutes (60 minutes works for me). Check for doneness by inserting a wooden toothpick or skewer into the centre of the bread, making sure that it comes out clean and batter free. If you see there is still some sticky batter on the toothpick, continue to bake for up to an additional 10 minutes as needed (all ovens vary a bit!).
When done, remove pan from the oven and place the pan on a rack to cool. Once cooled, gently loosen the sides if needed, and use the overhanging parchment paper to pull the loaf out of the pan. This loaf slices best when cooled, although I usually do sneak a slice (or two!) while it is still warm. Enjoy!