Mix the milk with the cream, the sugar and the zest from the lemon. Then cut the vanilla pod in half and scrape out the seeds. Add both the seeds and the empty vanilla pod to the pan. Now cover it with a lid and heat it up till it starts to steam. Then turn off the heat and let it infuse for at least 1 hour.
Meanwhile mix the egg yolk with the cornstarch. The cornstarch is traditionally not necessary, but I add it to stabilize the anglaise.
After the hour bring the liquid to a simmer and remove the lid. Then while stirring slowly add the hot liquid to the yolks.
Now pour it back into the pan and while stirring cook it till the temperature is 85 °C. If you don’t have a thermometer just keep an eye on the thickness.
Once it’s done pass it through a fine sieve. Using a ladle or spatula will make this a lot easier. Then cover it and let it cool down in your fridge.
After that give it a final mix and then keep it in your fridge for later.
