Mix the flour and pumpkin pie spice in a bowl and set it aside.
Beat the butter and granulated sugar until light, then add the pumpkin puree, egg yolk, and vanilla extract.
Stir the dry mixture into the wet mixture until a dough forms.
Wrap the dough and chill it for 30 minutes.
Heat the oven to 350 degrees and line a baking sheet with parchment.
Roll the dough to 1/4 inch thick and cut out jack-o'-lantern shapes with a cookie cutter.
Place the cutouts on the baking sheet and bake for 10 to 12 minutes until the edges are lightly golden.
Cool the cookies completely on a wire rack.
Stir the powdered sugar and milk together until smooth, then divide the icing into two bowls.
Tint one bowl orange and the other black.
Spread orange icing on each cookie and let it set.
Pipe black icing to draw jack-o'-lantern faces on top.