Preheat the oven to 350 F. In a large bowl, whisk together flour, sugar, cocoa powder, salt, and baking soda. Add in eggs, melted butter, and vanilla extract. Whisk until smooth.
Evenly pour half of the brownie batter into a greased 8-inch square baking dish. Top with 12 Oreo cookies. Pour the remaining brownie batter over the Oreo cookies.
Chop the remaining Oreo cookies into pieces, and top evenly over the brownie batter. Bake for 25-30 minutes.