Preheat the oven to 350 degrees F and line a 9 inch square pan with parchment paper.

In a small bowl, add the bittersweet chocolate and butter. Place over a small saucepan of simmering water, and stir often until fully melted. Remove from the double boiler and allow to cool for a few minutes.

Meanwhile, in a large bowl, add the sugars, eggs, and vanilla. Using an electric mixer, beat on high speed for about 5-6 minutes until the mixture has doubled in size.

While mixing on low speed, slowly pour in the chocolate butter mixture.

Once it is fully combined, add the flour, cocoa powders, and salt, and fold until fully combined.

Pour half of the brownie batter into the prepared pan, then top with whole Oreos and pieces to fill in the gaps. Add the rest of the brownie batter and smooth out the top with an offset spatula. Top with more Oreo pieces, if desired.

Bake the brownies for about 32-35 minutes. Allow them to cool completely in the pan before removing and cutting.

Use a sharp knife to cut the brownies into 16 squares. Enjoy!