(Excerpted from the COOLHAUS ICE CREAM BOOK © 2014 by Natasha Case, Freya Estreller with Kathleen Squires. Reproduced by permission of Houghton Mifflin Harcourt. All rights reserved. Photos by Brian Leatart. Makes about: 1½ quarts. Active time: 10 to 15 minutes)
Use the freshest eggs available for best results. If possible, refrigerate the base for a full 24 hours — the longer, the better. We like to chill our bases in plastic or stainless-steel pitchers with airtight lids for easy pouring into the ice cream maker after chilling.
2 cups whole milk
2 cups heavy cream
1¼ cups granulated sugar
8 large egg yolks
In a 4-quart saucepan, combine milk, cream, and half of sugar. Set over high heat, and cook, stirring occasionally, until mixture comes to a boil, about 5 minutes.
Meanwhile, in a medium bowl, whisk yolks and remaining sugar until smooth, heavy, and pale yellow, about 30 seconds.
When cream mixture just comes to a boil, whisk, remove from heat, and, in a slow stream, pour half of cream mixture over yolk-sugar mixture, whisking constantly until blended.
Return pan to stovetop over low heat. Whisking constantly, stream yolk-cream mixture back into pan.
With a wooden spoon, continue stirring until mixture registers 165 to 180 degrees F on an instant-read thermometer, about 2 minutes. Do not heat above 180 degrees F, or eggs in base will scramble. Mixture should be slightly thickened and coat back of spoon, with steam rising, but not boiling. (If you blow on the back of the spoon and the mixture ripples, you've got the right consistency.)
Pour base into a clean airtight container and refrigerate for 12 to 24 hours before using.
Use base within 3 to 5 days.