Do you have to put icing under the fondant on a cake?

* Stability: Fondant is thin and delicate. It can crack or tear easily if it's directly applied to the cake. A layer of buttercream or ganache provides a smooth, stable base for the fondant to adhere to.

* Flavor: A layer of icing underneath adds a layer of flavor and richness to the cake. This is especially important if the cake is dry or if the fondant itself doesn't have much flavor.

* Moisture barrier: Fondant can absorb moisture from the cake, causing it to become soggy. A layer of icing helps prevent this by creating a barrier between the cake and the fondant.

* Smoother finish: Even if you apply fondant to a perfectly smooth cake, small imperfections can still show through. An icing layer helps to even out the surface, resulting in a smoother, more professional-looking finish.

Exceptions:

* Fondant cakes for a specific look: Some cakes, like those with a crumb-coated finish, might not require a layer of icing under the fondant.

* Specialty fondant: Some fondant brands are specifically designed to be applied directly to the cake without an icing layer.

General rule of thumb: It's always best to err on the side of caution and use a layer of icing under your fondant. It will ensure a more stable, flavorful, and professional-looking cake.