Preheat your oven to 350 degrees and line an 8x8 inch baking pan with parchment paper. Set aside.
In a medium saucepan over low heat, melt the butter. Once the butter is melted, add the granulated sugar, cocoa powder and salt, stirring until well combined.
Let your butter mixture cool or put it in the refrigerator to chill for a few minutes. It just needs to cool enough that it doesn't cook your eggs when you add them to the mixture next.
Pour the butter mixture into a medium bowl and add the eggs and vanilla. Stir until combined with a spatula.
Add the flour and stir until just combined.
Fold in the chocolate chips.
Pour half of your batter into the 8x8 pan. I measured the weight of my batter with a scale so that I knew it would be perfect, but you can eyeball it as well.
Place whole Oreos evenly on top of the batter, filling most of the space. I used 12 Oreos here.
Pour the rest of your brownie batter over the top of the Oreos. Crush up chunks of your remaining Oreos and spread out on the top of the batter, pressing down slightly.
Bake for 30-35 minutes or until a toothpick comes out almost completely clean. You don't want it to overcook and be dry, so a few moist pieces on the toothpick is fine.
Allow the brownies to cool completely before cutting.