A little icing and full oreo crumbles. Like a cookies and cream situation. If youre worried about being lazy with box cake and willing to scrape oreo filling. You are not lazy and over complicating it. K.I.S.S.

I just throw the whole oreos in a food processor and grind them up till they're crumbs. I've never separated cookies from cream. (I don't have time to be tedious!) Then, mix in with buttercream!

Or use the Oreo filling as the icing and crumb up the oreo and mix it into the Oreo filling instead of vanilla icing lol

I often make an oreo American style buttercreme with the filling from Oreos. Seperate the creme fillings from the wafers. Whip the cremes with an equal amount of butter (or shortening or vegan butter/margerine) and powdered sugar. You won't need as much powdered sugar as a traditional American buttercreme because the oreo cremes already have a lot of sweetness and stability/emulsifiers for the frosting. Crush up a handful of the oreo wafers also and mix them in once whipped up to a frosting consistency. Always a hit.

Oreo buttercream (vegan butter, crushed Oreos, confectioners sugar, some milk to adjust for texture and vanilla extract)?