Step 1

Preheat the oven to 350°Fahrenheit (175°C). Line a 9x13-inch baking pan with parchment paper, leaving an overhang on the sides. Lightly grease the parchment with cooking spray and set aside.

Step 2

In a microwave-safe bowl, melt the butter and 4 ounces of chocolate in 30-second intervals until smooth. Add the cocoa powder and whisk well until lump-free.

Step 3

In a separate large bowl, beat the granulated and brown sugars with the eggs, yolk, and vanilla until thick and pale. Use an electric mixer on medium speed.

Step 4

Reduce the speed to low and blend in the melted chocolate and butter slowly while the mixer is running.

Step 5

Add the flour and salt and mix gently by hand until about halfway combined. Add the remaining chocolate and mix just until no streaks of flour are visible.

Step 6

Pour half the brownie batter into the prepared baking pan, spreading it evenly. Crumble half of the Oreos over the brownie batter, spacing them evenly across the surface. Spoon the remaining brownie batter over the crushed cookies, carefully spreading it with a spatula to cover the cookies completely.

Step 7

Top the brownie batter with more crushed Oreos or nestle whole Oreos evenly over the surface.

Step 8

Bake for 35-40 minutes until set around the edges but still slightly gooey in the center. A toothpick inserted in the center should come out with a few moist crumbs, but not entirely clean.

Step 9

Allow the brownies to cool completely. Then, lift them out using the parchment overhang and slice into squares. Enjoy!