Grilled Fluffernutter Sandwich also known as a Grilled Peanut Butter and Marshmallow Fluff Sandwich. Creamy peanut butter with marshmallow fluff or cream in between 2 pieces of bread and then cooked in a skillet for a warm, toasty gooey sandwich of deliciousness. If you have never had a Peanut Butter and Marshmallow Fluff Sandwich you are in for a real treat!