Sift together flour, cornstarch, milk powder, baking powder, baking soda, and kosher salt in a large mixing bowl.

Combine cold butter, light brown sugar, and granulated white sugar in a stand mixer. Mix on low speed until chunky.

Gradually mix in the dry ingredient mixture until crumbly.

Fold in chopped Gluten Free Oreos, dark chocolate chunks, and white chocolate chips until evenly distributed.

Whisk together eggs and vanilla extract; add to the dough and mix until incorporated.

Divide the dough into 6-ounce cookies, shape gently, wrap in plastic wrap, and refrigerate for at least 4 hours.

Preheat oven to 375°F (190°C), arrange chilled cookie pucks on a lined baking sheet, sprinkle with salt, and bake for 10 minutes.

Lower oven temperature to 350°F (175°C) and bake for an additional 7-9 minutes until edges are puffed.

Let cool on the baking sheet for 10 minutes before transferring to a wire rack.