Most readily accessible ice cream makers today include a gel insert that you put in the freezer overnight before pouring in the base and churning. We recommend using an old-fashioned hand-crank ice cream maker, which uses rock salt and ice to freeze the mixture. Rock salt rapidly drops the freezing temperature of ice and, in effect, makes a very, very cold slush that surrounds and freezes the ice cream. This slush reaches colder temperatures (and does so more quickly) than any gel freezer on the market. And the faster and colder you freeze your ice cream, the smoother and creamier it will be. This is because there’ll be less time for ice crystals to grow.