Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, cream the softened butter and sugar until light and fluffy, about 2–3 minutes.
Beat in the egg and vanilla extract until well combined.
Add the dry ingredients to the wet mixture in two additions, alternating with milk. Mix just until everything is combined don’t overmix!
Fold in the chopped candy corn using a spatula.
Scoop tablespoon-sized portions of dough onto the baking sheets, leaving 2 inches between each cookie.
Gently press 2–3 whole candy corn pieces on top of each dough ball for decoration.
Bake for 10–12 minutes, until edges are lightly golden. Keep an eye on them the candy corn melts quickly.
Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.