Clean, rinse and drain the gooseberries. Bring to a boil in a saucepan with sugar, water (I) and cinnamon stick and make 25 min. with the lid closed. Take out the cinnamon stick. Mash the gooseberries in a hand mixer (cool a little beforehand) or pass through a sieve. Cool.
In the meantime, whisk egg yolks with water (Ii) in a baking bowl until creamy*. Add sugar and vanilla sugar. Stir until you have a creamy mixture. Stir in cooled gooseberry puree by tablespoonfuls. In another baking bowl, whip whipped cream until stiff. Mix with the gooseberry puree. Fill into goblets. Place in the refrigerator for 20 minutes.
Bring to table sprinkled with pistachios.
*I would whip this in a water bath and then whip again when cooled.