Pour the cream into a saucepan together with the espresso, the sugar and the salt. Then cut the vanilla pod in half and scrape out the seeds. Add both to the pan and then heat it up till the liquid is 80 °C.
After that turn off the heat and cover the pan with a lid. Let it cool down completely.
Then remove the vanilla pod and add the egg yolk. Mix it well and then pass it through a fine sieve.
Now fill some glasses or ramakins to a third and use a blowtorch to remove any air bubbles that are floating on top. Then cover the glasses with some plastic wrap and make sure that they are completely sealed.
Now steam them at 91 °C for around 20 to 25 minutes depending on the size of the glasses. I steamed mine for 22 minutes. The custard needs to be set, but still a bit wiggly.
Then make a small hole in every glass and let them cool down completely in your fridge.
