Whisk together egg yolks and sugar in a medium bowl until thick and pale yellow.

Warm the milk, rose water, and vanilla in a medium saucepan over medium heat just until mixture lightly simmers. Gradually pour milk mixture into yolk mixture, whisking constantly.

Return mixture to saucepan and cook over medium-low heat, stirring constantly, until an instant-read thermometer registers 170°F and mixture is thick enough to coat the back of a spoon.

Remove from heat. Add saffron, stirring until mixture takes on a deep-yellow color, about 1 minute. Stir in whipping cream. Cover surface with plastic wrap; chill at least 8 hours or up to 24 hours.

Churn mixture in an ice cream maker according to manufacturer’s directions until it reaches the texture of soft-serve ice cream. Add pistachios during the last few minutes of churning.

Transfer to a freezer-safe container, cover surface with parchment paper, and freeze until firm.