Prepare the cupcake batter according to the box directions. And preheat the oven to 350 degrees.
Crush 10 oreos into large chunks and fold into the batter.
Bake according to box directions and cool completely after baking.
To prepare the frosting, add 10 oreos to your food processor and blitz until fine crumbs. Set oreo crumbs aside.
In a large mixing bowl, beat butter on medium speed until smooth.
Add powdered sugar, 1 cup at a time, mixing in between each addition. The frosting will still be powdery.
Add the vanilla and milk, and mix on high speed, as frosting begins to form.
Mix until well combined.
Add oreo crumbs, and mix a few seconds more to combine.
Use a frosting piping bag and your favorite frosting tip to pipe the frosting onto the cupcakes, then top each cupcake with the remaining 24 oreos.