Add the pistachios to a food processor and blend until they form a smooth, creamy paste, about 3-4 minutes, scraping down the sides occasionally. The natural oils will release and create a butter-like consistency. Blend until the mixture turns from coarse crumbs to a glossy spread.

Combine the milk, cream, and half the sugar in a medium saucepan over medium heat. Stir gently until the sugar dissolves completely and tiny bubbles form around the edges, but do not let it boil. The mixture is ready when you see wisps of steam rising from the surface.

Whisk the egg yolks with the remaining sugar in a separate bowl until pale and slightly thickened. Slowly pour about half a cup of the warm milk mixture into the yolks while whisking constantly. Gradually add another cup of the warm mixture, whisking continuously to raise the temperature of the yolks slowly and safely.

Pour the tempered egg mixture back into the saucepan with the remaining milk. Cook over medium-low heat, stirring constantly with a wooden spoon or silicone spatula until the custard coats the back of your spoon and reaches about 170°F, about 8-10 minutes. Draw your finger across the spoon—if the line stays clean, the custard is ready. Never let it boil.

Remove the custard from heat and stir in the pistachio paste, almond extract, and salt. Blend with an immersion blender until completely smooth and uniformly green. Strain the mixture through a fine-mesh sieve into a clean bowl. Press plastic wrap directly onto the surface to prevent a skin from forming, then refrigerate for at least 4 hours or overnight.

Pour the chilled custard into your ice cream maker and churn according to the manufacturer's instructions, typically 20-25 minutes, until the gelato has a soft-serve consistency. Transfer to a freezer-safe container, press parchment paper on the surface, and freeze for at least 3 hours before serving.