Preheat oven to 350°.
While the oven is preheating make the cookie dough. Cream together the butter and sugar until light and fluffy.
Scrape the sides, add in the eggs and vanilla extract. Beat until mixed.
Scrape the sides and add in the flour, & baking powder. Mix until thoroughly combined.
Add the chopped oreos to the mixing bowl and turn on the mixer for about 5 seconds- just long enough to mix in the cookies, not completely smash all of them.
Scoop out heaping 1/4 cup of dough and roll into a ball and then flattening them to the thickness and size you'd like your finished cookie. Repeat with remaining dough. The cookies will spread slightly so make sure to leave room. I tend to only put 6 cookies per pan.
Bake at 350° for 9-11 minutes or until the centers of the cookies have puffed up and are no longer glossy.
Allow them to cool on the cookie sheet.
While the cookies are cooling, make the frosting.
Cream the butter until smooth. Slowly add in the powdered sugar, vanilla extract and milk until smooth and creamy.
Add in the chopped Oreo and mix until the Oreo is mixed in, but not so much your frosting turns grey.
Spread on the completely cool cookie and top with a mini Oreo right in the middle.
Chill the cookies in the fridge until ready to serve. These cookies are served chilled.