Finely grind the pistachios in a food processor. Cut the vanilla bean lengthwise and scrape out the pulp. Place it in a pot with the whipped cream and sugar and let it simmer. Stir until the sugar has dissolved.

Remove the pot from the heat and blend the mixture again with the pistachios in a food processor. Then set aside for 30 minutes. Pass the mixture through a fine sieve and mix with vodka and amaretto. Fill into bottles and decorate.