Fondant

Fondant is a sugar syrup that is crystallized to a smooth, creamy white mass. It is familiar as the icing for napoleons, éclairs, petits fours, and some cakes. When applied, it sets up into a shiny, nonsticky coating.

The word crystallized in the previous paragraph may cause some confusion. In chapter 12, the discussion of cooking sugar syrups stressed avoiding crystallization because crystallization causes graininess. So how can crystallization occur in a smooth icing? Reading the procedure for making fondant, you will see that this white icing starts out as a sugar solution as clear as water. It is crystallization that turns it white and opaque. The key is to control the temperature so when the crystals form, they are microscopically tiny. Keeping them so small keeps the fondant smooth and shiny. If the fondant is not made correctly, or if it is heated too much when used, the crystals become larger and the icing loses its shine and its smoothness.