Preheat oven to 350°F. In a bowl, mix butter, granulated sugar, and brown sugar together using an electric mixer. When mixed, add egg and vanilla, then mix again until creamy and light brown.
Crush Oreo cookies into medium to small size pieces in a sealed, sturdy bag using a mallet or your hands.
Add flour, cocoa powder, crushed Oreo cookies, baking soda, baking powder, and salt. Thoroughly mix to combine.
Roll dough into balls with your hands into approximately ½ cup size or ¼ cup size for smaller cookies. Add to a baking sheet and press each ball lightly down with your palm to flatten them slightly.
Bake for 12 to 15 minutes, until the cookies begin to crack and are no longer shiny. Let them cool while you make the frosting, for at least 20 minutes.
In a bowl, whip together butter, vanilla, and cream cheese until smooth. Gradually add powdered sugar and continue mixing to combine completely.
Pour the frosting mixture into a large zip-lock bag with a corner cut off, or a piping bag with a round tip.
Pipe the frosting by starting from the middle of the cookie and slowly swirling outwards to form a spiral. Top with crushed oreos, serve, and enjoy!
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Notes
These cookies expand while they bake. If you want smaller cookies, roll them into half the size.
They can be stored in an airtight container in the fridge. To keep them moist, store with a slice of bread in the container (optional)
If you don't have a piping bag to frost the cookies with, use a plastic bag and cut part of one of the corners off with scissors.
For best results while baking, always level and measure your ingredients!
Use room temperature eggs and butter while baking.