Preheat your oven to 350°F (175°C) and line a 9x9 inch baking pan with parchment paper.

In a bowl, whisk together flour, cocoa powder, and sugar until well mixed.

Melt the butter, cool slightly, and then combine with the sugar mixture. Add the eggs one at a time, mixing well.

Fold the dry ingredients into the wet mixture until combined. Gently fold in chocolate chips and crushed Oreo cookies.

Transfer the batter to the prepared pan and spread evenly. Level off the batter with a spatula.

Decorate with whole Oreo cookies on top, evenly spaced.

Bake for approximately 32 minutes, checking for a soft center.

Let cool for 15-20 minutes before lifting out to slice into squares.