Begin by blanching 1 cup of shelled unsalted pistachios in boiling water for 1-2 minutes. Drain and cool slightly before rubbing off skins.

In a high-speed blender, blend the blanched pistachios with 2 cups of whole milk until smooth and creamy. Chill in the refrigerator overnight.

Strain the blended mixture through a fine-mesh sieve into a clean bowl for a velvety texture.

Heat the strained mixture in a saucepan over medium heat. Whisk in dissolved corn starch if necessary until it coats the back of a spoon.

Remove from heat and whisk in 3/4 cup of sugar, a pinch of salt, and pistachio extract. Stir in 1 cup of heavy cream until well combined.

Chill the combined mixture for 1-2 hours or use an ice bath for 30 minutes before churning.

Pour into an ice cream maker and churn for 20-30 minutes until thickened. Optionally fold in coarsely ground pistachios.

Transfer to an airtight container, cover with parchment paper, and freeze for at least 4 hours until firm.

Let the gelato soften for 5-10 minutes at room temperature before serving for optimal creaminess.