Store-bought oatmeal cream pies have a "vanilla creme" filling. Today, we're making a fluffy, vanilla marshmallow filling that is similar in texture and flavor, but even better. Many recipes use pre-made marshmallow fluff as the base of their filling, but we're making ours entirely from scratch (surprising, I know ). If you're not a fan of marshmallow cream or want a less labor intensive filling, I've included alternative options in the recipe notes!