Preheat oven to 350 degrees.
Line the cupcake pan with cupcake liners, and place an Oreo at the bottom of the liner.
In a large bowl, mix the cake mix, eggs, vegetable oil, and water until well combined.
Pour about 1/4-1/3 cup of cake mixture over the Oreo in the cupcake liner.
The liner should be about 3/4 of the way full.
Fill all the cupcake liners.
Place in oven and bake for about 20-25 minutes or until you can poke with a toothpick, and there is no batter on the toothpick.
Take out of oven and let cool completely.
In a medium sized bowl, add butter (at room temperature, not softened or melted at all), powdered sugar, vanilla, and milk.
Mix with a hand mixer until smooth and well combined.
If the texture is not to your desired thickness, you can add a little more powdered sugar.
Crush about 6 Oreo's in a bag or food processor.
Add the crushed Oreo's to the vanilla frosting, and mix in with a spoon.
Spread or pipe onto cooled cupcakes and enjoy! 🙂