Soak the shelled pistachios in water for several hours, then drain and blend with the milk until a creamy puree forms.

In a saucepan, gently heat the heavy cream with sugar, stirring until the sugar dissolves.

In a separate bowl, whisk together the egg yolks, cornstarch, and a pinch of salt. Gradually introduce the warm cream mixture into the yolks, whisking continuously.

Return the mixture to the saucepan and cook over low heat until it thickens, stirring continuously.

Remove from heat and stir in the pistachio puree and vanilla extract.

Pour the mixture into a bowl and let it cool to room temperature before refrigerating until set.

Serve the pistachio cream chilled in elegant glass dessert cups, garnished with crushed pistachios and optionally topped with whipped cream.

Cover the pistachio cream with plastic wrap, pressing it directly onto the surface to prevent a skin from forming, and store in the refrigerator for up to three days.