Position a rack in the middle of the oven. Preheat the oven to 350º F (180º C). Line a cookie sheet with parchment paper or silicone baking mat.
In a medium bowl, combine the flour, salt, and pumpkin spice, if using. Set aside.
In the bowl of an electric mixer beat together on medium speed the butter and brown sugar until fluffy, about 5 minutes. Beat in vanilla; mix to incorporate.
Reduce mixer’s speed to low. Add the flour mixture, mixing until just incorporated. If the dough looks grainy, don't worry, turn off the mixer and bring it together with your hands until uniform and smooth (like clay).
Roll the dough out, between two sheets of parchment paper, to 1/4-inch thickness. Use a cookie cutter to cut the dough into your desired shapes. Then transfer them to the prepared cookie sheet, spacing cookies about 1-inch apart.
Bake for 10-12 minutes or until the bottom is lightly browned. Cool on the pan for 2-3 minutes, before transferring to a wire rack to cool completely.
Decorate to your liking.