Whisk the flour, cocoa powder, baking powder, and salt in a medium bowl until evenly mixed.
In a separate bowl, beat the softened butter and sugar until light and creamy.
Add the egg and vanilla extract to the butter mixture and stir until combined.
Gradually mix the dry ingredients into the wet ingredients until a dough forms.
Wrap the dough in plastic and chill it for 30 minutes.
Heat the oven to 350 degrees and line a baking sheet with parchment paper.
Roll the chilled dough to 1/4-inch thickness on a lightly floured surface.
Cut out bat shapes with a cookie cutter and place them on the baking sheet.
Bake for 10 to 12 minutes until the edges look set.
Let the cookies cool completely on a wire rack.
Lightly brush the cooled cookies with edible silver luster dust using a small dry brush.