For anyone who loves chocolate, ganache, a mixture of chocolate and heavy cream, and sometimes a little butter, could be its own food group. Thick ganache, when rolled into balls, chilled, and dusted with cocoa, becomes truffles. When poured into a crust, it becomes a luxurious filling (page 474). Thinner ganache makes an elegant glaze for a cake. The secret to making ganache is to chop the chocolate very fine, to have the cream at a full boil, and to make certain that the butter, if you’re using it, is soft and creamy, almost like mayonnaise. Pour the cream over the chocolate, let it sit for a moment, and then gently stir the mixture, taking care not to beat air into it. Finally, stir in the butter. Ganache to be used for a glaze should rest until it is the pouring consistency you want. Ganache for a filling should be poured into the crust and chilled until set, then served after it’s had a little out-of-the-fridge time. Truffles should be served chilled.