In the bowl of a stand mixer, beat the butter and sugar together until creamy and smooth. Add the pumpkin, molasses, egg, and vanilla extract, mix until well combined.
In a medium bowl, whisk together flour, baking soda, spices, and salt. Add dry ingredients to wet ingredients and mix until combined. Refrigerate the cookie dough for at least 1 hour. The dough can be chilled for 2-3 days.
When you are ready to bake, preheat oven to 350° F. Line a baking sheet with a Silpat or parchment paper. Place sugar in a small bowl. Roll tablespoon-sized balls of dough in sugar until well coated and place on prepared baking sheet, about 2 inches apart. Bake for 10–12 minutes, or until cookies look cracked and set at the edges. The cookies will still be soft. Let the cookies cool on the baking sheet for a 2-3 minutes after removing them from the oven, then transfer to a wire rack to cool completely.