Heat oven to 350º. Line the bottom and sides of a 9×13-inch baking dish with foil or parchment, leaving an overhang on all sides. In a medium bowl, whisk together the flour, spices, baking soda and salt and set aside.

In the bowl of a stand mixer fitted with a paddle attachment or using a handheld mixer, cream the butter and sugar on medium high speed until smooth. Add the egg and vanilla and continue beating until well combined. Beat in pumpkin purée, then reduce speed to low and mix in dry ingredients until just blended. Using a rubber spatula, stir in chocolate chips.

Evenly spread batter in the prepared pan. Bake for 35-40 minutes, or until a toothpick inserted in the center comes out with only a few moist crumbs attached. Cool completely in pan. Use the foil/parchment overhang to remove the dessert from the pan, then cut into 24 squares and serve.

Keep any leftovers in an airtight container for up to 2 days.