Preheat the oven to 350 F. Line a 12 cup muffin pan with paper liners. In a large bowl, whisk together flour, sugar, cocoa powder, salt, and baking soda. Add in the eggs, melted butter, and vanilla extract until smooth.
Place one mint Oreo cookie in each paper liner. Evenly divide the brownie batter between the paper liners. Bake for 15-20 minutes.