Sift the flour, cocoa powder, baking powder, and salt together in a bowl. In a separate large bowl, beat the butter and sugar until smooth, then mix in the eggs one at a time along with the vanilla. Slowly add the dry ingredients until a soft, cohesive dough forms.
Place the dough between two sheets of parchment paper and roll it out to about a quarter-inch thickness. Chill the rolled dough in the fridge for at least an hour, or in the freezer for about 30 minutes, until it feels firm to the touch.
Once firm, use your pumpkin cookie cutter to cut shapes from the dough and place them on your lined baking sheets. On half of the pumpkins, use your paring knife to carve out small triangle eyes and a mouth for that classic jack-o'-lantern face.
Pop your baking sheets of cut-out dough back in the fridge for another 30 minutes, or the freezer for 15 minutes. This step keeps the shapes from spreading and losing their crisp pumpkin outline once they hit the oven.
Bake at 350°F for 8 to 9 minutes, just until the cookies are set but not overdone. Let them cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
Beat the cream cheese, butter, and vanilla together until smooth, then gradually mix in the powdered sugar. Add a few drops of orange gel coloring until you reach your desired shade. Spread frosting onto the plain pumpkin cookies, then top each with a jack-o'-lantern face cookie to make your sandwich.