Preheat the oven to 350°F. Line two baking sheets with parchment paper or silicone baking mats.

In the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl with a hand mixer), cream ¾ cup (170 g) unsalted butter and ¾ cup (150 g) granulated sugar on medium speed until light and fluffy, about 2–3 minutes.

Add 1 large egg and 1 teaspoon vanilla extract and mix until smooth and uniform.

In a separate bowl, whisk together 2 cups (248 g) all-purpose flour, ½ teaspoon baking soda, ½ teaspoon cream of tartar, 1 teaspoon pumpkin pie spice, and ½ teaspoon salt.

With the mixer on low speed, gradually add the dry ingredients to the butter mixture and mix just until combined. Do not overmix.

In a small bowl, stir together ⅓ cup (67 g) granulated sugar and 2 teaspoons pumpkin pie spice to make the coating.

Use a 2-tablespoon scoop or measure to portion the dough into 2-tablespoon balls. Roll each ball in the sugar–pumpkin spice mixture to fully coat.

Place the coated dough balls on the prepared baking sheets about 2 inches apart.

Bake for 9–11 minutes, or until the cookie bottoms just start to turn golden brown. For a softer, chewier cookie, err on the shorter end of the time.

Let the cookies cool on the baking sheet for at least 5 minutes, then transfer to a wire rack to cool completely. Store cooled cookies in an airtight container for up to 3 days or freeze for up to 1 month.