In a medium bowl, combine the flour, cornstarch, baking soda and salt. Set aside.
To the bowl of a stand mixer, add the butter, cream cheese, granulated sugar and brown sugar. Using the paddle attachment, combine on medium speed until smooth, about 2 minutes.
To the butter mixture, add the egg and vanilla extract. Mix on medium speed until combined. Stop the mixer and scrape the sides of the bowl.
With the mixer on low speed, gradually add the flour mixture and mix until combined - be careful not to over mix. Stop the mixer.
Add the crushed Oreos and mini chocolate chips and stir by hand until combined.
Cover the bowl with plastic wrap and chill in the refrigerator for 30 minutes.
Preheat oven to 350°F.
Line baking sheet with parchment or a silicone baking mat. Scoop cookies onto the prepared cookie sheet, about 2 Tablespoons each in size. Place cookies 2 inches apart.
Bake 12 minutes, or until the edges start to brown.
Remove from oven and allow cookies to cool on the baking sheet before transferring to a wire rack.