Preheat oven to 350 degrees, and grease a 9X5 inch loaf pan. Set aside.
If using the flax eggs, mix together your 2 tablespoons ground flax seeds and 6 tablespoons water, and set aside. (otherwise skip this step)
In a medium bowl, mix together your flour, baking soda, salt, and cinnamon. Set aside.
In a large bowl beat together your brown sugar and butter. You can use a stand mixer or hand mixer.
Mix until well blended, approx one minute.
Add your flax eggs (or 2 eggs), beat in.
With a large spoon, stir in your banana, pumpkin, and vanilla.
Slowly add in your dry ingredients. Your batter will be thick, but try not to over mix. Set aside.
Mix together your cinnamon sugar swirl mixture in a small bowl.
Spoon half the banana pumpkin batter into your greased loaf pan, and sprinkle with the cinnamon swirl mixture.
Top with the remaining batter.
Bake for 40 to 45 minutes, or until a knife or skewer comes out clean.
Cool in the pan on a wire rack for 15 minutes.
Remove from the pan and cool completely on the wire rack.