Line two baking sheets with silicone baking mats or parchment paper. Set aside.

Place the butter, brown sugar, and granulated sugar in a large mixing bowl. Use a hand mixerand beat on medium speed until well combined, about 1 minute. Add the egg, molasses, and vanilla and continue to beat until smooth, about 30 seconds.

Sift the flour, baking soda, ginger, pumpkin pie spice (or cinnamon), and salt into the butter mixture. Beat on low speed, scraping sides of bowl with a rubber spatula as needed, until a smooth dough forms.

Divide the cookie dough into 24 balls, using about 2 tablespoons for each, and arrange on the prepared baking sheets at least 1 inch apart. Transfer the baking sheets to freezer while oven preheats. Alternately, place the dough balls on a small baking sheet or large plate to freeze, and transfer to the large baking sheets before baking.

Preheat the oven to 350°F.

Bake the cookies on middle rack of oven until puffy and cracked, 15-17 minutes.

Check to see that cookies are done. Remove from oven or add time as needed.

Allow cookies to rest and firm up on baking sheets for 5-10 minutes, then transfer to a wire rack to cool completely before serving.