Preheat your oven to 350°F (175°C). Line two large baking sheets with parchment paper or silicone baking mats. This helps prevent sticking and makes cleanup a breeze.

In a medium bowl, whisk together the all-purpose flour, baking soda, salt, and pumpkin pie spice. Set this aside for a moment.

In a large bowl, using an electric mixer (stand or hand-held), cream together the softened butter, granulated sugar, and light brown sugar on medium speed until light and fluffy, about 2-3 minutes. Make sure to scrape down the sides of the bowl as needed to ensure everything is incorporated.

Beat in the large egg until just combined. Then, add the pure pumpkin puree and vanilla extract, mixing on low speed until fully incorporated. Don't worry if the mixture looks a little curdled at this stage; it will come together.

Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix; overmixing can develop the gluten and lead to tough cookies. Stop mixing as soon as no streaks of flour remain.

Gently fold in the semi-sweet chocolate chips with a rubber spatula until they are evenly distributed throughout the dough.

Drop rounded tablespoons of dough, or use a 1.5-inch cookie scoop, onto the prepared baking sheets, spacing them about 2 inches apart. Bake for 12-15 minutes, or until the edges are lightly golden and the centers are just set.

Let the cookies cool on the baking sheets for 5 minutes before carefully transferring them to a wire rack to cool completely. This crucial step helps them set up and prevents them from breaking.