Ganache is equal parts chocolate and cream melted together. From this union, all sorts of fantastic creations sprig forth. In melty liquid form, it is perfect on ice cream. Cooled, it can be scooped with a very small ice cream scoop or a tablespoon and rolled into balls and coated with cocoa powder to make truffles. But my favorite use for ganache is when it is cooled to room temperature and whipped into frosting. Basically, this is like making a very chocolately thick whipped cream. It is amazing.
Of course, the better the quality of chocolate, the better the ganache. I usually use Callebaut, but sometimes, after the holidays, I make ganache from all our leftover Fannie Mae candy from our Christmas stockings. To make ganache, heat cream to the scalding point (when little bubbles will form on the edges but not yet boiling) and stir the chocolate (cut into chunks) into the cream to melt it. Usually the heat from the cream will be enough to melt the chocolate. I measure the cream by volume and the chocolate by weight and I try to keep the proportions equal.