Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

In a large bowl, cream together the softened butter and sugar until light and fluffy. Beat in the egg and vanilla extract.

In another bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the butter mixture, mixing until the dough forms.

Roll out the dough on a floured surface to about 1/4 inch thickness. Use a round cookie cutter (or a glass) to cut out circles for Jack Skellington's face. Transfer the cookies to the prepared baking sheet.

Bake the cookies for 8-10 minutes, until the edges are just golden. Remove from the oven and let them cool completely.

Once the cookies are cool, cover them with a layer of white icing. Use black icing or black food coloring gel to draw Jack Skellington's signature face: large round eyes, two small nostrils, and a stitched smile.

Let the icing set before serving or packaging the cookies.