Preheat Oven: Preheat your oven to 350°F (175°C). Grease a 9×9-inch square baking pan with cooking spray and line it with parchment paper for easy removal.

Melt Butter and Chocolate: In a microwave-safe bowl, melt the butter and 1 cup of semisweet chocolate chips in the microwave, stirring every 20-30 seconds, until smooth and fully melted. Set aside to cool slightly.

Mix Wet Ingredients: In a large mixing bowl, whisk together the granulated sugar, eggs, and vanilla extract until smooth and slightly fluffy. Stir in the melted chocolate mixture.

Combine Dry Ingredients: In a separate bowl, whisk together the flour, cocoa powder, and salt. Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Add Chocolate Chips: Fold in the remaining 1 cup of semisweet chocolate chips.

Layer the Oreos: Spread half of the brownie batter into the prepared pan. Place 12 Oreo cookies evenly over the batter, pressing them down slightly. Top with the remaining brownie batter, spreading it to cover the Oreos.

Bake: Place the pan in the oven and bake for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. The brownies should be slightly firm to the touch but still soft in the center.

Cool and Serve: Let the brownies cool completely in the pan before cutting into squares and serving.