How to Make It
In a small bowl, whisk the flour, baking powder, baking soda and salt. In the bowl of a standing mixer fitted with the paddle, beat the butter and sugars at medium- high speed until light and fluffy, 4 minutes. Beat in the egg and vanilla. At low speed, beat in the dry ingredients, then beat in the Cornflake Crunch, chocolate chips and candy corn. Mound 1/4-cup scoops of dough 4 inches apart on 4 parchment–lined baking sheets. Flatten the cookies slightly and refrigerate until firm, about 3 hours.
Preheat the oven to 375° and position a rack in the center. Bake the cookies, one sheet at a time, for 15 minutes, until browned around the edges but still a bit pale in the center. Let cool completely on the tray, then serve.