In a small bowl, combine dry ingredients (flour, cinnamon, ginger, allspice, nutmeg, espresso powder, and salt). Set aside.
Combine the butter and sugars in the bowl of a stand mixer. Mix the butter only until incorporated. Scrape down the sides of the bowl, then mix briefly to incorporate. (Adding too much air to the dough will cause the cookies to spread, so avoid overmixing!)
Add pumpkin puree, eggs, and vanilla extract. Mix to combine, then scrape down the sides of the bowl.
Add dry ingredients. Mix until the dough begins to clump (do not overmix, or your cookies will be tough).
Turn the dough out onto a lightly floured surface. Knead briefly to form a ball. Cut the ball in half and form each half into a disc. Wrap each disc in plastic and chill in the refrigerator one hour.
Preheat oven to 350F. Working with one disc at a time, roll the dough out on a floured surface to about ¼ inch thick. Cut out desired shapes and place on parchment or silpat-lined baking sheets (see note).
Scraps may be re-rolled, and should be chilled as necessary so that the dough can be worked with easily. Place the baking sheets with the cut cookies in the refrigerator to chill for at least 10 minutes before baking.
After chilling, bake 8-12 minutes, or until edges are golden (see note). Allow cookies to cool completely on a wire rack.
For Royal Icing:
In the bowl of a stand mixer, combine water, meringue powder, and cream of tartar. Using the whisk attachment, beat mixture until soft peaks form. Stop the mixer and scrape down the sides as necessary.
With the mixer running on low speed, gradually add the powdered sugar. Beat mixture until combined.
Color royal icing as desired. I outlined my cookies in royal icing, To frost the rest of the cookie, add enough water (you won't need much!) to make the icing a pourable consistency, and "flood" the cookies with the remaining icing.
Royal icing dries out quickly, so be sure to keep it covered with plastic or inside squeeze bottles (see note) if you're not using it right away.Frost/decorate cookies as desired.Enjoy!
Notes
Note on espresso powder: I've found it difficult to find espresso powder--especially one that isn't already hard as a rock--at my local grocery store. I use King Arthur Flour's brand (link [here]), as it's very fine and made specifically for baked goods.Note on meringue powder: I can never find meringue powder in my local grocery store. You can find it in craft stores and cake decorating supply shops, and you can also find it online [here].Note on silpat: I use silpats (like this one [here]) when baking, which makes the cookies brown up a little slower and makes for easy cleanup. If you're lining your pans with parchment, your cookies will be done sooner.Note on bake time: The bake time will depend on the size of your cookies, so keep an eye on them! It's also a good idea to bake like-sized cookies together to ensure they're all done at the same time.Note on flooding cookies: I find that using squeeze bottles (like these [here]) to flood my cookies is much more convenient than trying to spoon it on.