Into a medium mixing bowl, sieve the flour and cocoa powder. Add in spices, salt, baking soda, and stir until well combined.
In a second bowl, whisk pumpkin puree, cashew butter, maple syrup* and vanilla extract.
Add in the flour mixture, and stir until well incorporated and there are no lumps left. Scoop the pumpkin pie brownie batter into the prepared baking pan and level it with a silicone spatula*, going all the way into the corners. Sprinkle with chocolate chips if desired.
Bake for 25-30 minutes or until a skewer inserted into the center of the brownie comes out clean.
Once the brownie is done, remove from oven and allow it to cool, then refrigerate for 1 hour to fully set. This will make the vegan pumpkin brownie super fudgy.
Remove from the refrigerator and cut into 9 squares.