When it comes to how each of these sugar doughs is worked, fondant, sugar paste, and marzipan are similar in many ways, although they do have some differences. Each is better for certain uses, depending on what you want for the finished product.
For example, fondant stays soft after it is shaped, making it suitable for covering cakes and applying two-dimensional decorations; sugar paste becomes hard and brittle once it dries, so it can hold a three-dimensional shape but should not be used to cover a cake. Sugar paste is most commonly used to create flowers, leaves, and any other decoration or shape that needs extra structure during sculpting. The added stability also provides longevity for decorating and storing. For instance, when ruffling the edge of a flower petal, sugar paste will hold the ruffle, while fondant would not. Tutorials on making various kinds of sugar paste flowers and leaves begin on page 137.
Marzipan has a grainy texture from the ground almonds. You can sculpt it like clay, but it isn’t the best for rolling out like fondant, or for making delicate shapes like sugar paste. It’s ideal for sculpting items such as fruits, which aren’t naturally super smooth, such as the peaches on page 169.
Fondant, sugar paste, and marzipan all act as a magnet for the smallest pieces of dust, whether from your hands, work surface, tools, or apron. So before you start working, clean all surfaces, including your rolling pin and any other tools, wear a clean apron, wash your hands or wear gloves, and use a nonporous nonstick surface (such as a large cutting mat or your countertop) and plastic or silicone rolling pin.
To roll out fondant or sugar paste, first knead it on a nonstick surface until it becomes malleable. Lightly dust your surface with powdered sugar (for fondant) or cornstarch (for sugar paste), then, using a plastic or silicone rolling pin, roll out the fondant or sugar paste like a piecrust, rotating it as necessary and making sure to keep the shape and thickness even. Generally I roll fondant for covering a cake to a thickness of ⅛ inch, and sugar paste for flowers and leaves very thinly, to about ¹⁄16 inch.
A multitude of cutters is available to make specific shapes from thinly rolled-out sugar paste, including leaves, flowers, shapes, letters, and numbers. Silicone molds can be used to transfer realistic textures onto sugar paste cutouts (such as veins on leaves, as on the Sweet Peas and Ferns cake on page 195), or to mold it into shapes (such as the Brooch Flowers cake on page 232). Sugar paste can also be rolled out and cut by hand to make custom shapes and designs, such as feathers (page 218) and flags (page 244).
To keep fondant or sugar paste from drying out, cover with a damp tea towel that has been wrapped in plastic wrap while working. If the fondant or sugar paste seems hard to work with or is cracking, it most likely is drying out. To bring it back to a workable material, knead a small amount of corn syrup or vegetable glycerin into it on a nonstick surface brushed with palm oil shortening. Knead the dough until all the ingredients are incorporated and it has a smooth, pliable texture.
The texture of the fondant or sugar paste often reflects the temperature of the environment and sometimes even the temperature of your hands. If it is sticking to your surface, hands, or rolling pin, lightly dust the work surface: Use powdered sugar for fondant (cornstarch would dry it out), and cornstarch for sugar paste (powdered sugar can add too much moisture and keep the decorations from drying properly).