from "baking bites" - http://bakingbites.com/2010/12/pumpkin-gingerbread-cookies/ - time does not include chill time of at least 2 hours for the dough, or time for the cookies to cool before icing
In a medium bowl, sift together flour, baking powder and salt.
In a large bowl, cream together sugar and butter. Beat in molasses, pumpkin puree, egg, spices and vanilla extract until well blended. With the mixer on low speed or by hand, gradually add in the flour mixture, mixing until no flour remains.
Divide dough into two pieces. Wrap in plastic wrap and chill for at least 2 hours.
Preheat oven to 375°F.
Working with 1 piece of dough at a time, roll out to no more than 1/4-inch thick on a lightly floured surface and use a floured cookie cutter to make desired shapes. Transfer cookies to a parchment lined baking sheet. Reroll reaming dough, chilling for a few minutes if it becomes too warm to handle easily. Repeat with second piece of dough. Dough can be rolled out two to three times.
Bake for 7-9 minutes at 375F, until the edges are slightly firm to the touch but cookies are not browned (The bottom of the cookies will be light brown). If your cookies are exceptionally large or small, the baking time may need to be adjusted. Cool completely on a wire rack before icing.
In a small bowl combine powdered sugar, milk and vanilla. Whisk until very smooth. Icing should be thick and pourable, but not runny (You can always add a bit of extra sugar to thicken it if you add too much). Scrape into piping bag with a fine tip or a ziploc bag with a corner cut off and pipe onto cooled cookies. Allow to set for at least 30 minutes, until firm, before storing cookies in an airtight container.