Preheat oven to 350 F. Line baking sheets with parchment paper or silicone baking mats. Set aside.
In a large bowl, beat butter and shortening together until well-combined.
Add sugars and beat until well-combined.
Mix in eggs and vanilla. Scrape down bowl as needed.
Add flour, cocoa powder, baking soda, and salt.
Stir in just until combined.
Add chopped cookies and chocolate chips.
Stir in just until combined.
Cover and chill dough for 30 minutes.
Scoop dough by 1.5 tablespoon scoops and place 2 inches apart on prepared baking sheet.
Bake for 8-11 minutes. The edges should be set but the middles should look soft and slightly underdone.
Cool on baking sheet for 10 minutes.
Transfer to a wire cooling rack to finish cooling.
Notes
Butter: I like to use salted butter, but you can use unsalted butter if you prefer. The butter should be at room temperature (72F). This means that the butter should be soft enough to dent when pressed but shouldn't lose shape when pressed. Overly warm butter can cause the cookies to bake out (spread too much).
Flour: It's important to properly measure the flour to avoid packing it in. To properly measure the flour, sift or stir the flour to break it up. Then lightly spoon into the measuring cup and level.
Cocoa powder: I use regular unsweetened cocoa powder in this recipe.
Oreo cookies: Feel free to change up the type of Oreos you use in the cookies. For example, you could use birthday cake oreos with funfetti or white chocolate chips.
Chocolate chips: I use semisweet chocolate chips, but you could use bittersweet, milk, white chocolate chips, or a combination of chips in these cookies.