Fondant is a thick type of icing made of sugar and water that is often flavored or colored. It’s used in the making of various candies and cakes because of its versatility and ability to be molded into whatever shape or design you desire.
Advantages: Fondant is great if you’re having an outside or summer wedding because it can stand up well to the heat. It’s also easier to make cut outs using fondant than trying to keep a steady hand and pipe with buttercream.
Disadvantages: Pound for pound, fondant is more expensive than buttercream because of the labor involved in the process of making and frosting the cake.
Buttercream is made by mixing butter, sugar and vanilla (some varieties use eggs) and any other flavor you wish to incorporate.
Advantages: Overall, the taste of buttercream is often preferred over the taste of fondant, especially by kids. It’s often what people are used to eating on cupcakes or cakes. Buttercream is also less expensive, and with fondant cakes, much of the icing ends up unconsumed on the plate. Buttercream can be used to pipe edges or any other decoration onto your cake for a uniform look.
Disadvantages: You should be careful using buttercream if your cake is going to be outside. To prevent melting, you’ll have to store it in a refrigerator. Oftentimes, buttercream also isn’t as smooth as fondant and it can be harder to fix if something on the cake gets distorted during transport.
The right choice depends on your taste and style, so you have to decide what’s most important to you.