Preheat the oven to 350 degrees.
Whisk together the dry ingredients in a medium bowl (flour, cocoa powder, baking powder, baking soda, and salt)
In a stand mixer, add the butter, brown sugar, and white sugar and beat for 3 minutes until light and fluffy, scraping down the sides.
Add in the egg yolks and vanilla extract and beat on low until combined.
Add in the dry ingredients and mix on low until combined.
Stir in the halloween sprinkles.
On a non stick baking tray or parchment lined tray, scoop out 12 cookie dough balls.
Bake for 9-11 minutes.
Top with more halloween sprinkles and serve your spooky treats!