Heat the cream and salt in a saucepan over medium heat until steaming and small bubbles form at the edge, about 5 minutes. Whisk the egg yolks in a bowl. Slowly pour hot cream into the yolks while whisking, then return the mixture to the pan.

Cook over low heat, stirring constantly, until the custard coats the back of a spoon and reaches 170°F (77°C), 5 to 7 minutes. Remove from heat and stir in the melted butter.

Transfer the custard to a bowl set over an ice bath. Stir occasionally until cool, then cover and refrigerate at least 4 hours, ideally overnight.

Churn in an ice cream maker per manufacturer’s instructions, about 20 to 25 minutes, until it looks like soft-serve. Serve right away, or freeze in a loaf pan for about 2 hours for a firmer scoop.