Don't worry, this comprehensive guide to the different kinds of icing, glazes and frostings is going to help you out!
Buttercream is a type of icing or filling used either inside cakes, as a coating, or as decoration.
It is a frosting superstar, popular and versatile. There are lots of different types, all made with a base of fat (often butter) and sugar.
Making this icing is a lot like making candy. You mix and boil brown sugar and milk, then combine with butter and sugar until spreadable. It will set firm on your cake.
Ganache is an emulsion of solid chocolate melted in cream sometimes with butter added. The amount of cream and chocolate can be varied.
It is pronounced as guh-nash, yes, thank me later haha.
A glaze in cooking is a coating of a glossy, often sweet, sometimes savoury, substance applied to food typically by dipping, dripping, or with a brush. Egg whites and basic icings are both used as glazes. They often incorporate butter, sugar, milk, and certain oils.
Gum paste is a pliable dough that cake decorators use. The mixture of egg whites, confectioners' sugar and shortening can be rolled quite thin, so it's very versatile. Unlike fondant, which remains soft, gum paste dries quite hard. That makes it better for cake decorations than for, say, covering an entire cake.
Ah, here comes the fancy. This is the type of icing that you're probably going use for cake decorating. Rolled fondant is a pliable, dough-like icing that's made of sugar, water, gelatin and food-grade glycerine. Its smoothness gives cakes a polished look but it's also flexible and workable enough to mold into shapes. Poured fondant remains pourable, developing a glossy finish as it dries. Look for it on top of fairy-tale pretty cakes or cupcakes.
Marzipan is a confection consisting primarily of sugar or honey and almond meal (ground almonds), sometimes augmented with almond oil or extract. It is often made into sweets; common uses are chocolate-covered marzipan and small marzipan imitations of fruits and vegetables.
Similar to fondant, but it will set hard (not firm); use it to make sculptural elements on cakes. It is often used in highly stylized works of cake art.
This basic mixture of egg whites, confectioners' sugar and often a touch of lemon has a consistency that can be piped, but it dries hard. A fave for ornate cookie decorations, royal icing can also be used to pre-make flowers or other cake decorations.
Use this delicious stuff as a frosting or filling for cakes. Commercial bakers typically use stabilized whipped cream, enforced with marshmallow, butter or gelatin for an extra firm texture that won't melt easily.
So, hopefully next time you will know, what is on that cake you're going to consume.