Put milk and cream in a saucepan. Cut the vanilla pod lengthways and add. Bring the whole thing to a boil and then take it off the stove and let it rest for 10 minutes.
Beat the egg yolks and sugar with a whisk to a pulpy mass. Take the sliced vanilla pod out of the mixture and scrape out the entire pulp and add to the milk.
Slowly add the warm cream and milk mixture to the pulpy egg yolk and sugar mixture and stir. Then put the whole thing in a saucepan and let it thicken for about 5 - 10 minutes over a very low heat while stirring.
Then let the mixture cool to room temperature in a bowl, stirring occasionally. The cooled mass is then best poured into a metal container, covered with cling film or baking paper and placed in the freezer.
After about 1 1/2 hours (the cream will not be frozen yet) stir again and smooth the cream on. Then put it back in the freezer and freeze again.