Briefly boil the milk with 1 g agar-agar and immediately remove it from the heat.
Stir 40 g pistachio paste into the hot milk mixture. Set aside the rest of the pistachio paste (approx. 20 g) for garnish.
Add the 50 g finely chopped white couverture and stir until a homogeneous paste forms.
Whip the 70 ml cream with 3 g cream stabilizer until stiff.
Let the pistachio mixture cool to about 35°C (95°F). Then carefully fold it into the whipped cream and mix everything well until a homogeneous cream forms.
Cover the pistachio cream and chill it overnight in the refrigerator.