Ganache

Hot cream is poured over finely chopped chocolate, left for a minute, then stirred from the center outward until glossy. The fat and water from the cream and the cocoa butter in the chocolate form an emulsion, which is why a good ganache looks shiny rather than oily.

The ratio of chocolate to cream decides the texture. With dark chocolate, equal weights give a pourable glaze that sets soft; about two parts chocolate to one part cream gives a firm ganache for truffles; less chocolate than cream gives a loose sauce or, once chilled, a whipped ganache. Milk and white chocolate contain less cocoa solids, so they need more chocolate for the same firmness.

If a ganache splits and looks greasy, a spoonful of warm cream stirred in, or a few seconds with an immersion blender, usually brings it back together.