An Oreo Crust + Oreo Buttercream= a sinful treat!!! Click here to get a 9x9 pan! Get Your Oreos Here! Oreo Bars Ingredients 40 Oreos, divided 1 c. butter, divided 3 c. powdered sugar 2 Tbsp. milk 1 tsp. vanilla Instructions Finely crush 30 Oreos in a food processor. Stir Oreo crumbs with ½ c.