In a medium bowl, whisk together flour, baking powder, and salt.
In a large mixing bowl, cream butter and sugar until light and fluffy.
Add egg and vanilla extract, mixing until combined.
Gradually mix in the dry ingredients until a dough forms.
Divide dough and dye a small portion with black food coloring for the ghost eyes and mouth.
Shape the remaining dough into a log. Insert small black dough bits to form ghost faces inside the log.
Wrap and chill the dough log for at least 2 hours.
Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
Slice chilled dough into cookies and place on prepared baking sheet.
Bake for 10–12 minutes or until edges are just turning golden.
Let cool and press candy eyes into the cookies if desired.