This treat is pure nostalgia! The signature soft texture and comforting cream combo of the oatmeal creme pie has become iconic. We heard the homemade version is even better, so we called in our friend Courtney Rich to share her recipe. The cookie is made up of a brown sugar and molasses base. Underbake the cookies just a tad so you nail the OG texture. Make sure you use quick-cooking oats (not old-fashioned)! Let the cookies cool completely before sandwiching them together with the marshmallow buttercream.