Heat the oven to 350 degrees and line a baking sheet with parchment paper.

In a mixing bowl, beat the softened butter and granulated sugar until light and fluffy. Add the egg and vanilla extract, then mix in enough orange gel food coloring to reach a bright pumpkin shade.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the butter mixture and stir until a smooth dough forms.

Roll the dough out on a lightly floured surface to about 1/4 inch thick. Use a pumpkin-shaped cutter to cut out shapes and place them on the prepared baking sheet.

Bake for 8 to 10 minutes until the edges turn lightly golden. Let the cookies cool completely on the sheet.

In a small bowl, stir the powdered sugar with 1 tablespoon of milk until smooth, adding more milk if needed for a pipeable consistency. Mix in black gel food coloring. Transfer the icing to a piping bag or zip-top bag with a small corner cut off, then pipe simple jack-o'-lantern faces onto the cooled cookies.