Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a medium mixing bowl, cream together the butter, brown sugar, and granulated sugar until smooth and fluffy.

Mix in the egg and vanilla extract until fully combined.

In a separate bowl, whisk together the flour, corn starch, baking soda, and salt. Gradually mix into the wet ingredients until just combined.

Fold in the chocolate chips and Halloween sprinkles evenly throughout the dough.

Scoop about 1/4 cup of dough, flatten it, place an Oreo in the center, and mold the dough around it to form a ball.

Arrange cookies on the baking sheet and bake for about 10 minutes until lightly golden.

Sprinkle extra chocolate chips on top immediately after removing from the oven and cool for 5 minutes before transferring to a wire rack.