The Day Before
Slightly roast the pistachios in a pan.

Bring the milk and cream to boil.

Remove from heat and immediately add the pistachios.

Cool down and let the pistachios soak in the milk-cream mixture overnight in the fridge.

The Next Day
Remove the pistachios from the milk-cream mixture into a food processor and pulse on high speed until it turns into a smooth paste.

Bring the milk-cream mixture to boil.

Beat the egg yolks and sugar in a bowl with an electric hand mixer until thick and fluffy.

As soon as the milk and cream are boiling, pour onto the eggs, stirring constantly with a whisk.

Pour the custard mixture back into the casserole and cook over low heat, stirring constantly with a wooden spoon, until it thickens. It should be around 181°F.

Cool the cream down in a water bath with ice cubes.

Stir in the pistachio paste and turn the cream into ice cream in an ice cream machine.