Preheat the oven to 350ºF and grease a 9x13 baking pan. Set aside.
In a medium bowl, whisk together flour, pumpkin pie spice, soda, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, cream butter and sugar on medium-high speed until smooth.
Beat in egg and vanilla until combined.
Add pumpkin puree and mix well.
Reduce the mixer speed to low and mix in dry ingredients just until combined.
Fold in the chocolate chips.
Spread the batter evenly in the prepared pan. Bake 35-40 minutes or until the edges begin to pull away from the sides of the pan and a toothpick inserted in the center comes out with a few moist crumbs attached.
Cool the bars completely in the pan. Cut into squares and serve.