Prep the Pistachios: In a food processor, finely grind the pistachios with 1/4 cup of granulated sugar until it forms a coarse paste.
Heat the Milk & Cream: In a saucepan, combine the whole milk and heavy cream. Heat over medium heat until it begins to simmer gently.
Whisk the Yolks: In a bowl, whisk together the egg yolks, remaining sugar, and a pinch of salt until the mixture becomes pale and thick.
Temper the Eggs: Gradually pour the hot milk mixture into the egg yolk mixture, whisking constantly to avoid curdling.
Cook the Mixture: Return the mixture to the saucepan, cooking over low heat while stirring, until it thickens enough to coat the back of a spoon without boiling.
Add Pistachio Paste: Remove from heat and stir in the pistachio paste and vanilla extract, ensuring everything is well combined.
Chill: Through a fine mesh sieve, pour the mixture into a bowl to remove lumps. Let it cool, cover, and refrigerate for at least 4 hours, or overnight.
Churn the Gelato: Once chilled, churn the mixture in an ice cream maker following the manufacturer's instructions until it reaches a soft-serve consistency.
Freeze: Transfer the gelato to a freezer-safe container and freeze for at least 2 hours, or until firm.
Serve & Enjoy: Scoop the gelato into bowls, garnish with additional chopped pistachios, and enjoy!