Preheat the oven to 350°F. Line a 9x13 with foil or parchment paper and spray with cooking spray, set aside. In a medium-sized bowl whisk together the flour, pumpkin pie spice, baking soda, and salt, set aside.
In the body of a stand mixer with the paddle attachment cream together the dark brown sugar, butter, and granulated sugar until smooth, 2 minutes.
Add the egg and beat until combined.
Add the pumpkin and vanilla, beat until smooth.
Next, add the dry ingredients to the wet and mix until combined with no dry patches.
Add in the chocolate chips.
Fold into blondie batter..
Press the dough into the prepared baking dish. I find it easier to spread with slightly moistened hands.
Bake for 40-45 minutes until a toothpick inserted into the center comes out clean.
Let cool completely, cut, and serve.