Pre-heat oven to 350 degrees and line a 9x13 pan with foil.
Whisk flour, pumpkin pie spice, baking soda, and salt in a medium bowl.
In the bowl of a mixer or in a large bowl with a hand mixer, cream butter and sugar together on medium-high until light and fluffy, about 3 minutes. Beat in the egg and vanilla until they’re combined. Beat in pumpkin puree. The mixture may look a bit curdled at this point, but don't worry.
Mix the dry ingredients into the wet ingredients with mixer on low until just combined. Fold in chocolate chips.
Spread batter into prepared pan and bake for 35-38 minutes, until edges are just starting to turn golden and an inserted toothpick comes out clean.
Let cool completely in pan before removing (by pulling foil out) and cutting into squares.