For the pistachio paste

1. Preheat the oven to 150° and in the meantime, line a baking tray with baking paper. Sprinkle the pistachios on top and roast in the preheated oven for 10 mins.
2. Put the pistachios in the food processor and add the Zusto. Finely chop them and continue processing until the oil in the nuts is released (this may take about 10 mins). When the oil is released and the paste becomes more liquid, add a teaspoon of sunflower oil and continue to mix it all together into a spreadable paste.

For the ice cream

1. Separate the eggs and set the egg whites to one side. Begin to whisk the egg yolks and carefully spoon in the Zusto. Continue to mix until a fluffy batter is formed.
2. Pour the soy milk into a saucepan and add the pistachio paste. Bring to a boil (add some green food colouring if you want). Remove the milk from the heat and carefully pour it over the egg mixture. Mix it all with a whisk. 
3. Then pour the entire mixture back into the saucepan and reheat. Continue to stir as the mixture thickens.
4. Once the mixture has thickened, remove it from the heat. Leave the ice cream mixture in the refrigerator for 1 more night before turning it into ice cream.
5. Remove the ice cream mixture from the fridge and continue preparing the ice cream by following your ice cream maker’s instructions (for me, this was about 20-25 mins in my KitchenAid).
6. You can eat the ice cream immediately or spoon it into a storage container. Store the ice cream in the freezer.