Combine the milk, rice, salt, and split vanilla bean in a large heavy-bottomed saucepan. If using vanilla extract, do not add it yet. Bring to a boil over high heat, stirring constantly.

Reduce the heat to low, cover, and simmer gently for 15 minutes, stirring occasionally.

While the pudding simmers, whisk together the egg yolks, sugar, and vanilla extract (if using) in a medium bowl until fully combined. Set aside.

Uncover and continue simmering, stirring frequently, until the rice is tender and the pudding has thickened. Do not let it boil. Stir constantly toward the end to prevent the milk from scorching, then remove the vanilla bean and scrape all the seeds into the pudding.

Slowly ladle the hot rice mixture into the egg yolk mixture, whisking constantly to prevent the eggs from scrambling. Return the entire mixture to the saucepan and cook over low heat, stirring, until thick enough to coat the back of a spoon, about 5 minutes.

Remove from the heat and transfer to a serving dish or storage container. Press a piece of parchment or plastic wrap directly against the entire surface to prevent a skin from forming. Refrigerate until cold, at least 2 hours.

Serve cold topped with crushed pistachios and a sprinkle of cinnamon.