Preheat the oven to 350F then line a baking sheet with parchement paper and set aside.
In a food processor, grind the 25 oreos until finely crushed. In a medium bowl, mix the crushed oreos, flour, corn starch, cocoa powder, baking soda, baking powder, cream of tartar, and salt then set aside.
In a stand mixer bowl, cream the softened butter, brown sugar, powdered sugar, and granulated sugar until light and creamy.
Add in the egg and the oil and mix again until combined. Scrape the bowl when needed.
Add in the dry mixture in two increments mixing in between every time until the dry mixture disappears. Then using a large cookie scoop, scoop out 10 equally sized cookie dough balls and bake in the preheated oven for 8-9 minutes.
Let the cookies cool on the baking sheet for 5-10 minutes before transferring them to a cooling rack.