Line a square 8x8 baking pan with parchment paper to cover all four sides. Then preheat the oven to 350 F/180 C.
Melt the butter and chocolate chips together until smooth. Then whisk in both cocoa powders. Set aside.
Whisk the sugar, eggs, and vanilla extract until combined. Stream the melted chocolate mixture into the egg mixture until just combined.
Fold in the flour, espresso powder, and salt until just combined. Then pour half of the brownie batter into the prepared baking pan (about 340 grams).
Place the Oreo cookies on top of the batter, then spread the rest of the batter on top. Sprinkle the chopped Oreos over the top of the brownies. Then bake for 33-40 minutes, or until a toothpick inserted into the center comes out covered in a few moist crumbs.
Let the baking pan cool on a wire rack compeltely before cutting into 16 squares. Enjoy!
Store leftover brownies in an airtight container at room temperature for 2-3 days. You can also freeze the brownies after cutting in an airtight container or freezer bag for up to one month!
Video
Notes
*Measure your dry ingredients properly. This is my #1 baking tip! Do not ever scoop a measuring cup into your flour, as this always leads to using too much flour. Instead, use the spoon-level method. This means fluffing the flour first, then spooning it into your measuring cup/spoon. For the BEST results, use a kitchen scale!*