I saw this on a few sites with minimal directions. I decided to rewrite it to make it easier & better. I used Betty Crocker's Ultimate Fudge Brownie mix & regular Oreos. Feel free to use any brownie mix.
Prepare brownie mix according to the directions on the box. Use a large spoon to mix the batter, not a whisk or a wooden spoon. (I use a large metal spoon from my silverware). Set bowl aside.
Lightly spray a 24 count cupcake tray with Pam Baking Spray. Holding one Oreo in your hand, lightly cover the top cookie with peanut butter. Top with another Oreo. Lightly cover top cookie with peanut butter. Place stack into the cupcake tin. Continue making stacks & filling the tin with Oreos.
Spoon the brownie batter over the Oreos, one spoonful is enough. It will slowly cascade over the Oreo stack.
Bake for 25 minutes. Check with a toothpick along the edge of the brownie to avoid the Oreo & peanut butter. Toothpick must be clean for the brownies to be done.
Allow brownies to cool in the pan for about 15 minutes on a wire rack. Using a butter knife, gently loosen brownies from the cupcake tray. Eat & enjoy with a glass of milk.
For an even better dessert, place the brownie in a dessert bowl. Add a scoop of ice cream. Add Hershey's chocolate or Caramel syrup, sprinkles, Cool Whip or RediWhip.