Heat cream, milk, vanilla seeds, and pod in a saucepan over medium until steaming, about 5 minutes. Remove from heat, cover, and steep 30 minutes.

Whisk egg yolks and sugar in a bowl until pale and thick, about 2 minutes. Remove vanilla pod from milk.

Slowly whisk half of the warm milk into the yolk mixture, then return everything to the saucepan. Cook over medium-low, stirring constantly, until thickened and 170°F to 175°F, about 5 to 7 minutes.

Strain custard through a fine-mesh sieve into a bowl. Stir in salt. Set bowl in an ice bath and cool, about 30 minutes. Cover and refrigerate until cold, at least 4 hours.

Churn in ice cream maker according to manufacturer’s instructions until soft-serve texture, 20 to 25 minutes. Transfer to a container, press plastic wrap on surface, and freeze until firm, at least 4 hours. Let soften 5 minutes at room temperature, then scoop.