Turn off heat and add cacao powder, maple syrup, pumpkin puree, pumpkin pie spice and salt; whisk until smooth. Add flour and whisk until well combined. Add remaining 1/2 cup chocolate chips and give a few stirs.
Pour into previously prepared baking dish, smooth with a spatula and bake for 25 minutes. Remove from the oven and let cool for a few hours. Cut into 16 squares and enjoy warm if you like brownies cakey moist or cold for extra fudgy experience.