Bring a pot of water to a boil, add shelled pistachios, and simmer for about 1 minute. Drain and rinse under cold water.

Gently pinch each pistachio to remove the skins or rub them in a kitchen towel.

Pat the peeled pistachios dry with a kitchen towel.

Blend the dried pistachios in a blender until they form a thick paste.

In a mixing bowl, add pistachio paste, softened butter, and sugar. Blend until smooth.

In another bowl, combine cold heavy cream, whole milk, vanilla extract, and a pinch of sea salt. Fold this into the pistachio base.

Whip the mixture using an electric mixer until stiff peaks form, about 3-5 minutes.

Transfer to an airtight container and chill in the refrigerator for at least 30 minutes before serving.