The secret to great homemade ice cream isn’t just the ingredients. According to Jon Snyder, owner of the Lower East Side’s celebrated Il Laboratorio del Gelato, it’s also the machine. You need one with built-in refrigeration. The average American freezer just doesn’t get cold enough to properly chill the ice-cream mixture, so you end up with a mushy mess that’s closer to a “dairy treat” than the gourmet confections available at Il Laboratorio. Snyder recommends the Gelato by Lello ($200 at Zabar’s). This totally self-contained device has a minimum freezing temperature of -4 degrees Fahrenheit. Prep the ingredients (for example, cut-up fresh fruit, diced nuts, or coffee), switch the machine on, and, 30 minutes later, you’ve got one quart of perfect ice cream.