The main difference is that fudge contains dairy ingredients like cream and butter, while fondant is just sugar and flavorings. Fudge is creamy and smooth, but fondant comes in two kinds. Rolled fondant is like clay, and poured fondant is like gelatin. Fudge is used in candy or eaten alone, and fondant is typically a decorative icing or frosting. Fudge is a lot thicker and denser and takes more time to make.