1. Preheat oven to 375 degrees F. Line a baking sheet with a Silpat baking mat or parchment paper. Set aside.
2. In a medium bowl, sift flour, baking soda, salt, and cocoa. Set aside.
3. With a mixer, cream butter and sugars together until smooth. Add in eggs, one at a time. Next, add in vanilla extract. Mix until blended.
4. Slowly add flour mixture to sugar mixture and mix until flour disappears. Stir in chocolate chunks and Oreos. Drop cookie dough by rounded tablespoons onto prepared baking sheet, about 2 inches apart.
5. Bake cookies for 8-10 minutes. Don't over bake. Remove from oven and let sit on baking sheet for 3-5 minutes. Move to a cooling rack and cool completely.