Preheat oven to 350 degrees.
Line a 9×13 baking dish with parchment paper. Set aside.
Prepare the brownie mix according to the directions on the package.
Chop 16 Oreo cookies into quarters and mix them into the brownie batter.
Chop the remaining Oreo cookies into quarters putting them into another bowl. Set aside.
Spread the batter evenly in the pan.
Bake at 350 degrees for 30-35 minutes.
Check the brownies to see if they are completely cooked.
Once baked, put the baking pan on a wire rack allowing the brownies to cool.
Bring a saucepan filled with water to simmering.
Put a heat-safe bowl on top of the pot of simmering water.
Pour the white chocolate and heavy cream into the bowl. Stir constantly until melted. Take white chocolate chips and heavy cream mixture in the bowl off the heat.
Stir in the peppermint extract.
Now add a few drops of green food coloring. Stir well to combine. (You can add more mint extract, up to 1/2 teaspoon.)
Quickly pour the panache on top of the brownies.
Sprinkle the remaining chopped Oreos on top of the panache. Sprinkle on the red candies.
Chill the brownies, allowing the ganache to set for at least an hour.
Cut the brownies into bars.