Preheat oven to 375°F. Line 2 baking sheets with parchment.
Make dough: Whisk together first 7 ingredients. In a separate bowl, cream butter and brown sugar until pale; beat in eggs. Mix in pumpkin, evaporated milk and vanilla, followed by flour mixture gradually.
Put some dough in a large plastic bag; snip a corner. Pipe 2 1/2-inch rounds about 1/2-inch thick onto sheets. Continue with rest of dough. Bake, rotating halfway through, until tops spring back when touched, about 12 minutes. Top each with a half marshmallow; bake for 1 1/2 minutes. Transfer, on parchment, to racks; cool.
Make icing: Using an electric mixer, beat cream cheese and butter until smooth. Add confectioners' sugar a little at a time until icing is thick but spreadable. Add food coloring.
Gently frost cookies over marshmallow. Let set for 20 minutes. Pipe icing faces and stems onto each cookie.
Time consuming? Yes, but what took the time was piping on the faces on the pumpkins. Dropping the ingredients into the bowl wasn't the hard part. The cookies came out nice and soft with a perfect balance of spices. The marshmallow made for a nice surprise with that first bite and the cream cheese frosting gave it that little bit of extra sweet for a nice finish. I would definitely make these again, but not as an every-day cookie. Recipe was good as-it, wouldn't (and didn't!) change a thing!