Melt together peanut butter, marshmallow creme and margarine. When blended together, add Cheerios. Stir in brown sugar. Pat into buttered 9-inch-by-13-inch pan. Cool and cut into squares.
Recipe by Amish 365 at https://www.amish365.com/5-amish-cook-christmas-recipes-church-windows-peanutty-squares/