Preheat the oven to 350 degrees F.
In a large bowl, beat together the brownie mix, egg, and butter that has been softened to room temperature. Do not melt the butter.
Beat in the cocoa powder and then the white flour. Slowly add the white flour until the dough is easy to shape into a cookie ball. You may need a few tablespoons up to 1/2 cup.
The dough may appear crumbly and that's normal! Knead together the dough with your hands until a thick dough has formed.
Knead in the chocolate chips. Barely cover a Mint oreo with the cookie mixture -- if you put too much cookie dough around the oreos they don't do as well.
If desired, top the cookies with a few more chocolate chips.
Bake for 12-14 minutes and then remove from the oven. (Baking time may vary based on the size of your cookies)
Allow to continue to "bake" on the cookie sheet for an additionally 3-4 minutes before removing them to a cooling rack.
Slightly under-baking these cookies will make them ultra fudgy and chewy!