In a microwave-safe mug, add milk and Oreos.
Use a fork to crush the Oreos into a paste.
Mix in 2 tsp vegetable oil, vanilla, and sugar.
Mix flour, cocoa powder, baking powder, and salt into the mug. Stir until it is combined.
Dip a whole Oreo biscuit into the batter.
Microwave on high for 60-90 seconds until baked properly.
Serve it with hot melted chocolate and crushed Oreos on top.