1-Preheat the oven to 350 degrees F and line baking sheets with parchment paper.

2-In a mixer bowl fitted with a paddle attachment, beat the butter and sugars on medium speed until light and fluffy (about 3 minutes).

3-Scrape down the bowl; add the vanilla extract and egg, beating well to combine.

4-In a separate bowl, whisk together the flour, cocoa powder, cornstarch, salt, baking soda, and baking powder.

5-Gradually add the dry ingredients to the wet ingredients, beating until a slightly sticky dough forms.

6-Fold in the white chocolate chips and Halloween-themed candies using a rubber spatula.

7-Using a cookie scoop, drop 3-tablespoon sized dough balls on the prepared baking sheets, spaced 2 inches apart.

8-Decorate the dough balls with extra chocolate chips, Halloween-themed candies, and edible candy eyes.

9-Bake for about 12 minutes until puffy but still soft; avoid overbaking.

10-Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.