Preheat your oven to 350°F. Line two baking sheets with parchment paper and set them aside.
In a medium bowl, mix together the flour, salt, and baking powder. Set that aside too.
In a large bowl, use an electric mixer (or stand mixer) on medium speed to beat the butter and sugar for about 2 minutes, until it looks light and fluffy.
Add the egg and vanilla. Scrape down the sides of the bowl so everything gets mixed in well.
Add the flour mixture and mix on low until the dough starts to form. Then use a rubber spatula to gently fold and press the dough so all the flour is fully mixed in.
Divide the dough in half. Take one half and roll it out on parchment paper or a silicone mat until it’s about ¼ inch thick. Do the same with the second half.
Cover with plastic wrap and put both rolled-out dough sheets in the fridge for 2 hours so they can chill.
After chilling, use your favorite Halloween cookie cutters to cut out shapes. We used bats and ghosts. Place the cookies on your lined baking sheets, making sure to leave about 1 inch of space between each one.
Bake for 10 to 12 minutes, or until lightly browned around the edges.
Let the cookies cool on the baking sheet for 5 minutes, then move them to a wire rack to cool completely.