Preheat oven to 350. Line a few baking trays with parchment paper.
Cream the butter and sugar until light and fluffy. Add the vanilla and eggs and beat until fluffy and combined.
Scrape down the bowl and add the baking powder and beat and scrape down the bowl a few times to evenly incorporate it. Then with the mixer on low add the flour and mix only until combined.
Smash the 12 oreos in a ziploc bag and add them and mix only for about 5-10 seconds until just mixed.
Scoop 1/4 cup portions of dough onto the parchment and roll into balls. Use a greased back of a glass or measuring cup to flatten the cookies to about 1/2-3/4 inches thick.
Only put about 4 cookies on a sheet because these are meant to be big cookies.
Bake about 9-10 minutes until the centers are puffed and no longer shiny, but don't overbake them. The edges should only be starting to brown.
Remove from oven and let cool for 5 minutes, then move to a cooling rack to finish cooling.
Coming the butter and powdered sugar and vanilla in the mixer and beat until mixed. Slowly add the cream until you get a smooth and creamy consistency. Not to thick and not too thin. Crush the 8 oreos in a bag and then add them and gently fold in so they don't turn your frosting too gray. Spread frosting on cooled cookies and top with a mini oreo.