Begin by boiling the shelled, unsalted pistachios in a pot of water for just 1 minute. Drain and rinse under cold water.

Gently pinch each pistachio to pop it out of its skin.

Spread the pistachios on a clean towel or paper towel and pat them dry.

Place the dried pistachios into a blender or food processor and pulse until finely ground.

Transfer ground pistachios to a mixing bowl and add softened unsalted butter and granulated sugar. Mix until smooth.

Process the mixture while gradually adding milk until a velvety paste forms.

In another bowl, combine the paste with cold heavy cream, whole milk, vanilla extract, and sea salt. Blend until incorporated.

Whip the mixture on medium-high speed until stiff peaks form.

Adjust sweetness or flavor by adding more sugar or extracts, then chill for at least 30 minutes before serving.