For Gelato: Put chocolate and sugar in a medium metal bowl. In a small saucepan, combine cream and salt; heat just to a boil, then remove from heat and pour over chocolate. Stir until chocolate has dissolved and custard is combined, then stir in milk. Chill custard in refrigerator, covered, until very cold, at least 4 hours or overnight. Freeze custard in an ice cream maker. (Gelato keeps in an airtight container, frozen, for up to 5 days.) 

 

For Pistachios: Heat oven to 275º. Line a baking sheet with parchment paper.

 

In a small bowl, combine water and salt; stir to dissolve salt. 

 

Add nuts and stir to combine. Spread mixture on prepared baking sheet and bake, stirring once halfway through, until nuts are dry and lightly golden, about 20 minutes. Transfer to a wire rack to cool completely. (Nuts keep in an airtight container for up to 2 days.)

 

Using a mini ice cream scoop, scoop 10 individual servings gelato and place into small bowls. Garnish with nuts.