Preheat oven to 350°F (175°C) and grease a 9x9 inch baking pan or line with parchment paper.
In a large bowl, whisk together the pumpkin puree, eggs, maple syrup, and vanilla extract until smooth.
In a separate medium bowl, combine oat flour, baking powder, baking soda, pumpkin pie spice, and salt.
Gradually stir the dry ingredients into the wet ingredients until no dry streaks remain.
Fold in the dark chocolate chips evenly throughout the batter.
Spread the batter into the prepared pan and smooth the top with a spatula.
Bake for 22 to 25 minutes or until a toothpick inserted into the center comes out clean.
Allow the bars to cool completely in the pan on a wire rack before slicing into 12 squares.