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 and mix until smooth.
Spread half of the batter into a greased 8-inch square baking dish. Place Oreos in a single layer on the batter. Cover with the remaining half of the brownie batter. Bake for 20-25 minutes.