To make a half-gallon of basic ice cream, Roberts offers a very specific formula.  Plenty of simpler recipes work. But we present Roberts’ for those who want to try their hand at culinary science:

• 417g skim milk
• 243g sugar
• 638g evaporated milk
• 726g cream

or

• 971g skim milk
• 243g sugar
• 85g nonfat dry milk
• 726g cream

Blend the skim milk and sugar until the sugar dissolves (heat the mix, don’t heat the mix — doesn’t matter, as long as the sugar disappears). Add the evaporated milk or the dry milk, and then add the cream. Follow the freezing directions on your ice cream maker.