Preheat the oven to 350 degrees F. Grease a 10 inch cast iron skillet (or similar size) with coconut oil or avocado oil.
In a large bowl, make the flax egg by mixing the ground flaxseed with the water. Set aside to thicken for 5 minutes.
In a medium bowl, add the oat flour, baking soda, baking powder, cinnamon, pumpkin pie spice, and salt. Whisk until well combined.
To the bowl with the flax eggs, add the ripe bananas and mash until smooth. Add the pumpkin, almond butter, vanilla, maple syrup, and apple cider vinegar. Whisk until well combined.
Add the dry ingredients to the wet. With a spatula, stir until combined, careful not to over mix! Pour batter into the cast iron skillet.
Make the cinnamon swirl by combining the coconut sugar, almond milk, and cinnamon in a small bowl. Put dollops of the cinnamon mixture all over the top of the batter. Lightly swirl it in the batter with a knife or toothpick.
Bake for 30 minutes or until a toothpick comes out clean. Let it cool for 30 minutes before eating. Enjoy warm with a dollop of coconut yogurt on top and a drizzle of maple syrup if desired. Store in an airtight container on the counter for up to 3 days.