Pre-heat the oven to 350º. Line a baking sheet with parchment paper.
Start by combining the flax seed with water in a small bowl. Whisk, then set aside.
Combine the oats, flour, baking powder and pumpkin spice mix in a large bowl.
In a medium bowl, combine the flax seed mixture, pumpkin purée, mashed banana, maple syrup and melted coconut oil. Whisk well to incorporate the oil within the mixture.
Pour the wet mixture over the bowl with the dry ingredients and stir until combined. I like to use a spatula to scrape the sides and bottom of the bowl to ensure there are no dry pockets anymore.
Divide the dough in between 8 cookies and transfer to the prepared baking sheet, then gently flatten them while keeping them thick. Top with the chocolate chips and bake for 12-14 minutes. The cookies might seem a little undercooked and very soft when just taken out of the oven, but let them cool down for a few minutes and they'll finish up cooking. Avoid over baking!