In a medium saucepan, over medium high heat, add the heavy cream and milk and bring to a boil, stirring to prevent any scalding on the bottom of the pan. Remove from the heat. To prevent the egg yolks from scrambling, temper them by adding only a ½ cup of the hot cream to start to the egg yolks with the mixer running. This will gradually increase the temperature of the egg yolk mixture keeping the eggs from cooking. Continue adding the cream mixture ½ cup at a time, until all the cream has been added. Check the temperature of the base, it should be 160°F | 71°C. If not, add back to the saucepan and heat to 160°F | 71°C, to pasteurize. Place the saucepan onto a bowl of ice water to chill.